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FAILED: patch "[PATCH] xhci: Disable stream for xHC controller with" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x cd65ee81240e8bc3c3119b46db7f60c80864b90b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025070814-harmonica-eclipse-ad04@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From cd65ee81240e8bc3c3119b46db7f60c80864b90b Mon Sep 17 00:00:00 2001 From: Hongyu Xie <xiehongyu1(a)kylinos.cn> Date: Fri, 27 Jun 2025 17:41:20 +0300 Subject: [PATCH] xhci: Disable stream for xHC controller with XHCI_BROKEN_STREAMS Disable stream for platform xHC controller with broken stream. Fixes: 14aec589327a6 ("storage: accept some UAS devices if streams are unavailable") Cc: stable <stable(a)kernel.org> Signed-off-by: Hongyu Xie <xiehongyu1(a)kylinos.cn> Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> Link: https://lore.kernel.org/r/20250627144127.3889714-3-mathias.nyman@linux.inte… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c index 6dab142e7278..c79d5ed48a08 100644 --- a/drivers/usb/host/xhci-plat.c +++ b/drivers/usb/host/xhci-plat.c @@ -328,7 +328,8 @@ int xhci_plat_probe(struct platform_device *pdev, struct device *sysdev, const s } usb3_hcd = xhci_get_usb3_hcd(xhci); - if (usb3_hcd && HCC_MAX_PSA(xhci->hcc_params) >= 4) + if (usb3_hcd && HCC_MAX_PSA(xhci->hcc_params) >= 4 && + !(xhci->quirks & XHCI_BROKEN_STREAMS)) usb3_hcd->can_do_streams = 1; if (xhci->shared_hcd) {

3 days, 21 hours

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FAILED: patch "[PATCH] xhci: Disable stream for xHC controller with" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x cd65ee81240e8bc3c3119b46db7f60c80864b90b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025070814-pebbly-diffused-9cd9@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From cd65ee81240e8bc3c3119b46db7f60c80864b90b Mon Sep 17 00:00:00 2001 From: Hongyu Xie <xiehongyu1(a)kylinos.cn> Date: Fri, 27 Jun 2025 17:41:20 +0300 Subject: [PATCH] xhci: Disable stream for xHC controller with XHCI_BROKEN_STREAMS Disable stream for platform xHC controller with broken stream. Fixes: 14aec589327a6 ("storage: accept some UAS devices if streams are unavailable") Cc: stable <stable(a)kernel.org> Signed-off-by: Hongyu Xie <xiehongyu1(a)kylinos.cn> Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> Link: https://lore.kernel.org/r/20250627144127.3889714-3-mathias.nyman@linux.inte… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c index 6dab142e7278..c79d5ed48a08 100644 --- a/drivers/usb/host/xhci-plat.c +++ b/drivers/usb/host/xhci-plat.c @@ -328,7 +328,8 @@ int xhci_plat_probe(struct platform_device *pdev, struct device *sysdev, const s } usb3_hcd = xhci_get_usb3_hcd(xhci); - if (usb3_hcd && HCC_MAX_PSA(xhci->hcc_params) >= 4) + if (usb3_hcd && HCC_MAX_PSA(xhci->hcc_params) >= 4 && + !(xhci->quirks & XHCI_BROKEN_STREAMS)) usb3_hcd->can_do_streams = 1; if (xhci->shared_hcd) {

3 days, 21 hours

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FAILED: patch "[PATCH] xhci: dbc: Flush queued requests before stopping dbc" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x efe3e3ae5a66cb38ef29c909e951b4039044bae9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025070847-wooing-headway-a75d@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From efe3e3ae5a66cb38ef29c909e951b4039044bae9 Mon Sep 17 00:00:00 2001 From: Mathias Nyman <mathias.nyman(a)linux.intel.com> Date: Fri, 27 Jun 2025 17:41:22 +0300 Subject: [PATCH] xhci: dbc: Flush queued requests before stopping dbc Flush dbc requests when dbc is stopped and transfer rings are freed. Failure to flush them lead to leaking memory and dbc completing odd requests after resuming from suspend, leading to error messages such as: [ 95.344392] xhci_hcd 0000:00:0d.0: no matched request Cc: stable <stable(a)kernel.org> Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver") Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> Link: https://lore.kernel.org/r/20250627144127.3889714-5-mathias.nyman@linux.inte… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c index 0d4ce5734165..06a2edb9e86e 100644 --- a/drivers/usb/host/xhci-dbgcap.c +++ b/drivers/usb/host/xhci-dbgcap.c @@ -652,6 +652,10 @@ static void xhci_dbc_stop(struct xhci_dbc *dbc) case DS_DISABLED: return; case DS_CONFIGURED: + spin_lock(&dbc->lock); + xhci_dbc_flush_requests(dbc); + spin_unlock(&dbc->lock); + if (dbc->driver->disconnect) dbc->driver->disconnect(dbc); break;

3 days, 21 hours

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[PATCH v4 1/1] mm/rmap: fix potential out-of-bounds page table access during batched unmap

by Lance Yang

From: Lance Yang <lance.yang(a)linux.dev> As pointed out by David[1], the batched unmap logic in try_to_unmap_one() may read past the end of a PTE table when a large folio's PTE mappings are not fully contained within a single page table. While this scenario might be rare, an issue triggerable from userspace must be fixed regardless of its likelihood. This patch fixes the out-of-bounds access by refactoring the logic into a new helper, folio_unmap_pte_batch(). The new helper correctly calculates the safe batch size by capping the scan at both the VMA and PMD boundaries. To simplify the code, it also supports partial batching (i.e., any number of pages from 1 up to the calculated safe maximum), as there is no strong reason to special-case for fully mapped folios. [1] https://lore.kernel.org/linux-mm/a694398c-9f03-4737-81b9-7e49c857fcbe@redha… Cc: <stable(a)vger.kernel.org> Reported-by: David Hildenbrand <david(a)redhat.com> Closes: https://lore.kernel.org/linux-mm/a694398c-9f03-4737-81b9-7e49c857fcbe@redha… Fixes: 354dffd29575 ("mm: support batched unmap for lazyfree large folios during reclamation") Suggested-by: Barry Song <baohua(a)kernel.org> Acked-by: Barry Song <baohua(a)kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Acked-by: David Hildenbrand <david(a)redhat.com> Signed-off-by: Lance Yang <lance.yang(a)linux.dev> --- v3 -> v4: - Add Reported-by + Closes tags (per David) - Pick RB from Lorenzo - thanks! - Pick AB from David - thanks! - https://lore.kernel.org/linux-mm/20250630011305.23754-1-lance.yang@linux.dev v2 -> v3: - Tweak changelog (per Barry and David) - Pick AB from Barry - thanks! - https://lore.kernel.org/linux-mm/20250627062319.84936-1-lance.yang@linux.dev v1 -> v2: - Update subject and changelog (per Barry) - https://lore.kernel.org/linux-mm/20250627025214.30887-1-lance.yang@linux.dev mm/rmap.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index fb63d9256f09..1320b88fab74 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1845,23 +1845,32 @@ void folio_remove_rmap_pud(struct folio *folio, struct page *page, #endif } -/* We support batch unmapping of PTEs for lazyfree large folios */ -static inline bool can_batch_unmap_folio_ptes(unsigned long addr, - struct folio *folio, pte_t *ptep) +static inline unsigned int folio_unmap_pte_batch(struct folio *folio, + struct page_vma_mapped_walk *pvmw, + enum ttu_flags flags, pte_t pte) { const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY; - int max_nr = folio_nr_pages(folio); - pte_t pte = ptep_get(ptep); + unsigned long end_addr, addr = pvmw->address; + struct vm_area_struct *vma = pvmw->vma; + unsigned int max_nr; + + if (flags & TTU_HWPOISON) + return 1; + if (!folio_test_large(folio)) + return 1; + /* We may only batch within a single VMA and a single page table. */ + end_addr = pmd_addr_end(addr, vma->vm_end); + max_nr = (end_addr - addr) >> PAGE_SHIFT; + + /* We only support lazyfree batching for now ... */ if (!folio_test_anon(folio) || folio_test_swapbacked(folio)) - return false; + return 1; if (pte_unused(pte)) - return false; - if (pte_pfn(pte) != folio_pfn(folio)) - return false; + return 1; - return folio_pte_batch(folio, addr, ptep, pte, max_nr, fpb_flags, NULL, - NULL, NULL) == max_nr; + return folio_pte_batch(folio, addr, pvmw->pte, pte, max_nr, fpb_flags, + NULL, NULL, NULL); } /* @@ -2024,9 +2033,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, if (pte_dirty(pteval)) folio_mark_dirty(folio); } else if (likely(pte_present(pteval))) { - if (folio_test_large(folio) && !(flags & TTU_HWPOISON) && - can_batch_unmap_folio_ptes(address, folio, pvmw.pte)) - nr_pages = folio_nr_pages(folio); + nr_pages = folio_unmap_pte_batch(folio, &pvmw, flags, pteval); end_addr = address + nr_pages * PAGE_SIZE; flush_cache_range(vma, address, end_addr); @@ -2206,13 +2213,16 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, hugetlb_remove_rmap(folio); } else { folio_remove_rmap_ptes(folio, subpage, nr_pages, vma); - folio_ref_sub(folio, nr_pages - 1); } if (vma->vm_flags & VM_LOCKED) mlock_drain_local(); - folio_put(folio); - /* We have already batched the entire folio */ - if (nr_pages > 1) + folio_put_refs(folio, nr_pages); + + /* + * If we are sure that we batched the entire folio and cleared + * all PTEs, we can just optimize and stop right here. + */ + if (nr_pages == folio_nr_pages(folio)) goto walk_done; continue; walk_abort: -- 2.49.0

3 days, 22 hours

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[PATCH] fs/ntfs3: Fix a resource leak bug in wnd_extend()

by Haoxiang Li

Add put_bh() to decrease the refcount of 'bh' after the job is finished, preventing a resource leak. Fixes: 3f3b442b5ad2 ("fs/ntfs3: Add bitmap") Cc: stable(a)vger.kernel.org Signed-off-by: Haoxiang Li <haoxiang_li2024(a)163.com> --- fs/ntfs3/bitmap.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ntfs3/bitmap.c b/fs/ntfs3/bitmap.c index 04107b950717..65d05e6a0566 100644 --- a/fs/ntfs3/bitmap.c +++ b/fs/ntfs3/bitmap.c @@ -1371,6 +1371,7 @@ int wnd_extend(struct wnd_bitmap *wnd, size_t new_bits) mark_buffer_dirty(bh); unlock_buffer(bh); /* err = sync_dirty_buffer(bh); */ + put_bh(bh); b0 = 0; bits -= op; -- 2.25.1

3 days, 22 hours

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Re: [PATCH v3] drm/framebuffer: Acquire internal references on GEM handles

by Thomas Zimmermann

Hi Am 07.07.25 um 18:14 schrieb Satadru Pramanik: > Applying this patch to 6.16-rc5 resolves the sleep issue regression > from 6.16-rc4 I was having on my MacBookPro11,3 (Mid-2014 15" > MacBookPro), which has the NVIDIA GK107M GPU enabled via the Nouveau > driver. Thanks for testing. I think the sleep regression was just a side effect of the broken reference counting. Best regards Thomas > > Many thanks, > > Satadru > > On Mon, Jul 7, 2025 at 9:33 AM Thomas Zimmermann <tzimmermann(a)suse.de> > wrote: > > Hi > > Am 07.07.25 um 15:21 schrieb Christian König: > > >> > >> +#define DRM_FRAMEBUFFER_HAS_HANDLE_REF(_i) BIT(0u + (_i)) > > Why the "0u + (_i)" here? An macro trick? > > You mean why not just BIT(_i)? internal_flags could possibly contain > additional flags. Just using BIT(_i) would make it look as if it's > only > for those handle refs. > > Best regards > Thomas > > > > > Regards, > > Christian. > > > >> + > >> /** > >> * struct drm_framebuffer - frame buffer object > >> * > >> @@ -188,6 +191,10 @@ struct drm_framebuffer { > >> * DRM_MODE_FB_MODIFIERS. > >> */ > >> int flags; > >> + /** > >> + * @internal_flags: Framebuffer flags like > DRM_FRAMEBUFFER_HAS_HANDLE_REF. > >> + */ > >> + unsigned int internal_flags; > >> /** > >> * @filp_head: Placed on &drm_file.fbs, protected by > &drm_file.fbs_lock. > >> */ > > -- > -- > Thomas Zimmermann > Graphics Driver Developer > SUSE Software Solutions Germany GmbH > Frankenstrasse 146, 90461 Nuernberg, Germany > GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman > HRB 36809 (AG Nuernberg) > -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)

3 days, 22 hours

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[PATCH v2 1/3] drm/amdgpu: Dirty cleared blocks on free

by Arunpravin Paneer Selvam

Set the dirty bit when the memory resource is not cleared during BO release. v2(Christian): - Drop the cleared flag set to false. - Improve the amdgpu_vram_mgr_set_clear_state() function. Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam(a)amd.com> Suggested-by: Christian König <christian.koenig(a)amd.com> Cc: stable(a)vger.kernel.org Fixes: a68c7eaa7a8f ("drm/amdgpu: Enable clear page functionality") --- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 1 - drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h | 5 ++++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 9c5df35f05b7..86eb6d47dcc5 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -409,7 +409,6 @@ static int amdgpu_move_blit(struct ttm_buffer_object *bo, if (r) { goto error; } else if (wipe_fence) { - amdgpu_vram_mgr_set_cleared(bo->resource); dma_fence_put(fence); fence = wipe_fence; } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h index b256cbc2bc27..2c88d5fd87da 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h @@ -66,7 +66,10 @@ to_amdgpu_vram_mgr_resource(struct ttm_resource *res) static inline void amdgpu_vram_mgr_set_cleared(struct ttm_resource *res) { - to_amdgpu_vram_mgr_resource(res)->flags |= DRM_BUDDY_CLEARED; + struct amdgpu_vram_mgr_resource *ares = to_amdgpu_vram_mgr_resource(res); + + WARN_ON(ares->flags & DRM_BUDDY_CLEARED); + ares->flags |= DRM_BUDDY_CLEARED; } #endif -- 2.43.0

4 days

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[PATCH AUTOSEL 5.4 1/3] Revert "ACPI: battery: negate current when discharging"

by Sasha Levin

From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com> [ Upstream commit de1675de39aa945bad5937d1fde4df3682670639 ] Revert commit 234f71555019 ("ACPI: battery: negate current when discharging") breaks not one but several userspace implementations of battery monitoring: Steam and MangoHud. Perhaps it breaks more, but those are the two that have been tested. Reported-by: Matthew Schwartz <matthew.schwartz(a)linux.dev> Closes: https://lore.kernel.org/linux-acpi/87C1B2AF-D430-4568-B620-14B941A8ABA4@lin… Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- **YES**, this commit should be backported to stable kernel trees. ## Extensive Explanation: ### 1. **Critical Userspace Regression Fix** This revert fixes a critical regression that breaks userspace applications. The commit message explicitly states that the original change "breaks not one but several userspace implementations of battery monitoring: Steam and MangoHud." This is a clear violation of the kernel's "no userspace regressions" rule, which is one of the most fundamental principles in kernel development. ### 2. **Code Analysis Shows ABI Change** Looking at the code changes: ```c // The problematic code that was added (and is now being removed): if (psp == POWER_SUPPLY_PROP_CURRENT_NOW && (battery->state & ACPI_BATTERY_STATE_DISCHARGING) && acpi_battery_handle_discharging(battery) == POWER_SUPPLY_STATUS_DISCHARGING) val->intval = -val->intval; ``` This code was changing the sign of the current value when discharging, which altered the userspace-visible ABI. Even if the original behavior didn't match documentation, changing it broke existing applications that depended on the long-standing behavior. ### 3. **Simple and Safe Revert** The commit is a clean revert that: - Removes the problematic sign negation logic - Restores the original behavior that userspace applications expect - Is self-contained to the `acpi_battery_get_property()` function - Has minimal risk of introducing new issues ### 4. **Meets Stable Kernel Criteria** According to stable kernel rules, this commit qualifies because it: - **Fixes a real bug** that users are hitting (broken battery monitoring in Steam and MangoHud) - **Is obviously correct** (it's a revert of a change that broke userspace) - **Is small and contained** (only affects the ACPI battery property reporting) - **Has been tested** (the reporter confirmed the issue) - **Fixes a regression** (restores previous working behavior) ### 5. **Comparison to Similar Commits** Looking at the historical commits marked with "Backport Status: YES", they share similar characteristics: - Fix actual problems affecting users - Are relatively small and contained changes - Don't introduce new features or architectural changes - Focus on fixing specific issues This revert fits perfectly into this pattern as it's fixing a specific userspace compatibility issue without introducing any new functionality. ### 6. **Timing Considerations** The original problematic commit (234f71555019) was from May 8, 2025, and this revert is from July 3, 2025. If the original commit made it into any stable releases, those stable trees would need this revert to prevent userspace breakage. ### Conclusion: This is a textbook example of a commit that should be backported to stable kernels. It fixes a userspace regression, is minimal in scope, carries very low risk, and restores previously working behavior that applications depend on. The fact that it's a revert of a problematic change makes it even more suitable for stable backporting. drivers/acpi/battery.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index a5e120eca7f33..cf853e985d6d9 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -266,23 +266,10 @@ static int acpi_battery_get_property(struct power_supply *psy, break; case POWER_SUPPLY_PROP_CURRENT_NOW: case POWER_SUPPLY_PROP_POWER_NOW: - if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN) { + if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN) ret = -ENODEV; - break; - } - - val->intval = battery->rate_now * 1000; - /* - * When discharging, the current should be reported as a - * negative number as per the power supply class interface - * definition. - */ - if (psp == POWER_SUPPLY_PROP_CURRENT_NOW && - (battery->state & ACPI_BATTERY_STATE_DISCHARGING) && - acpi_battery_handle_discharging(battery) - == POWER_SUPPLY_STATUS_DISCHARGING) - val->intval = -val->intval; - + else + val->intval = battery->rate_now * 1000; break; case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN: -- 2.39.5

4 days, 6 hours

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[PATCH AUTOSEL 5.10 1/3] Revert "ACPI: battery: negate current when discharging"

by Sasha Levin

From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com> [ Upstream commit de1675de39aa945bad5937d1fde4df3682670639 ] Revert commit 234f71555019 ("ACPI: battery: negate current when discharging") breaks not one but several userspace implementations of battery monitoring: Steam and MangoHud. Perhaps it breaks more, but those are the two that have been tested. Reported-by: Matthew Schwartz <matthew.schwartz(a)linux.dev> Closes: https://lore.kernel.org/linux-acpi/87C1B2AF-D430-4568-B620-14B941A8ABA4@lin… Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- **YES**, this commit should be backported to stable kernel trees. ## Extensive Explanation: ### 1. **Critical Userspace Regression Fix** This revert fixes a critical regression that breaks userspace applications. The commit message explicitly states that the original change "breaks not one but several userspace implementations of battery monitoring: Steam and MangoHud." This is a clear violation of the kernel's "no userspace regressions" rule, which is one of the most fundamental principles in kernel development. ### 2. **Code Analysis Shows ABI Change** Looking at the code changes: ```c // The problematic code that was added (and is now being removed): if (psp == POWER_SUPPLY_PROP_CURRENT_NOW && (battery->state & ACPI_BATTERY_STATE_DISCHARGING) && acpi_battery_handle_discharging(battery) == POWER_SUPPLY_STATUS_DISCHARGING) val->intval = -val->intval; ``` This code was changing the sign of the current value when discharging, which altered the userspace-visible ABI. Even if the original behavior didn't match documentation, changing it broke existing applications that depended on the long-standing behavior. ### 3. **Simple and Safe Revert** The commit is a clean revert that: - Removes the problematic sign negation logic - Restores the original behavior that userspace applications expect - Is self-contained to the `acpi_battery_get_property()` function - Has minimal risk of introducing new issues ### 4. **Meets Stable Kernel Criteria** According to stable kernel rules, this commit qualifies because it: - **Fixes a real bug** that users are hitting (broken battery monitoring in Steam and MangoHud) - **Is obviously correct** (it's a revert of a change that broke userspace) - **Is small and contained** (only affects the ACPI battery property reporting) - **Has been tested** (the reporter confirmed the issue) - **Fixes a regression** (restores previous working behavior) ### 5. **Comparison to Similar Commits** Looking at the historical commits marked with "Backport Status: YES", they share similar characteristics: - Fix actual problems affecting users - Are relatively small and contained changes - Don't introduce new features or architectural changes - Focus on fixing specific issues This revert fits perfectly into this pattern as it's fixing a specific userspace compatibility issue without introducing any new functionality. ### 6. **Timing Considerations** The original problematic commit (234f71555019) was from May 8, 2025, and this revert is from July 3, 2025. If the original commit made it into any stable releases, those stable trees would need this revert to prevent userspace breakage. ### Conclusion: This is a textbook example of a commit that should be backported to stable kernels. It fixes a userspace regression, is minimal in scope, carries very low risk, and restores previously working behavior that applications depend on. The fact that it's a revert of a problematic change makes it even more suitable for stable backporting. drivers/acpi/battery.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index 4a188cc28b5ce..f9fb092f33a26 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -255,23 +255,10 @@ static int acpi_battery_get_property(struct power_supply *psy, break; case POWER_SUPPLY_PROP_CURRENT_NOW: case POWER_SUPPLY_PROP_POWER_NOW: - if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN) { + if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN) ret = -ENODEV; - break; - } - - val->intval = battery->rate_now * 1000; - /* - * When discharging, the current should be reported as a - * negative number as per the power supply class interface - * definition. - */ - if (psp == POWER_SUPPLY_PROP_CURRENT_NOW && - (battery->state & ACPI_BATTERY_STATE_DISCHARGING) && - acpi_battery_handle_discharging(battery) - == POWER_SUPPLY_STATUS_DISCHARGING) - val->intval = -val->intval; - + else + val->intval = battery->rate_now * 1000; break; case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN: -- 2.39.5

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[PATCH AUTOSEL 5.15 1/3] Revert "ACPI: battery: negate current when discharging"

by Sasha Levin

From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com> [ Upstream commit de1675de39aa945bad5937d1fde4df3682670639 ] Revert commit 234f71555019 ("ACPI: battery: negate current when discharging") breaks not one but several userspace implementations of battery monitoring: Steam and MangoHud. Perhaps it breaks more, but those are the two that have been tested. Reported-by: Matthew Schwartz <matthew.schwartz(a)linux.dev> Closes: https://lore.kernel.org/linux-acpi/87C1B2AF-D430-4568-B620-14B941A8ABA4@lin… Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- **YES**, this commit should be backported to stable kernel trees. ## Extensive Explanation: ### 1. **Critical Userspace Regression Fix** This revert fixes a critical regression that breaks userspace applications. The commit message explicitly states that the original change "breaks not one but several userspace implementations of battery monitoring: Steam and MangoHud." This is a clear violation of the kernel's "no userspace regressions" rule, which is one of the most fundamental principles in kernel development. ### 2. **Code Analysis Shows ABI Change** Looking at the code changes: ```c // The problematic code that was added (and is now being removed): if (psp == POWER_SUPPLY_PROP_CURRENT_NOW && (battery->state & ACPI_BATTERY_STATE_DISCHARGING) && acpi_battery_handle_discharging(battery) == POWER_SUPPLY_STATUS_DISCHARGING) val->intval = -val->intval; ``` This code was changing the sign of the current value when discharging, which altered the userspace-visible ABI. Even if the original behavior didn't match documentation, changing it broke existing applications that depended on the long-standing behavior. ### 3. **Simple and Safe Revert** The commit is a clean revert that: - Removes the problematic sign negation logic - Restores the original behavior that userspace applications expect - Is self-contained to the `acpi_battery_get_property()` function - Has minimal risk of introducing new issues ### 4. **Meets Stable Kernel Criteria** According to stable kernel rules, this commit qualifies because it: - **Fixes a real bug** that users are hitting (broken battery monitoring in Steam and MangoHud) - **Is obviously correct** (it's a revert of a change that broke userspace) - **Is small and contained** (only affects the ACPI battery property reporting) - **Has been tested** (the reporter confirmed the issue) - **Fixes a regression** (restores previous working behavior) ### 5. **Comparison to Similar Commits** Looking at the historical commits marked with "Backport Status: YES", they share similar characteristics: - Fix actual problems affecting users - Are relatively small and contained changes - Don't introduce new features or architectural changes - Focus on fixing specific issues This revert fits perfectly into this pattern as it's fixing a specific userspace compatibility issue without introducing any new functionality. ### 6. **Timing Considerations** The original problematic commit (234f71555019) was from May 8, 2025, and this revert is from July 3, 2025. If the original commit made it into any stable releases, those stable trees would need this revert to prevent userspace breakage. ### Conclusion: This is a textbook example of a commit that should be backported to stable kernels. It fixes a userspace regression, is minimal in scope, carries very low risk, and restores previously working behavior that applications depend on. The fact that it's a revert of a problematic change makes it even more suitable for stable backporting. drivers/acpi/battery.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index b0a5d077db905..8bb0f4d06adc0 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -250,23 +250,10 @@ static int acpi_battery_get_property(struct power_supply *psy, break; case POWER_SUPPLY_PROP_CURRENT_NOW: case POWER_SUPPLY_PROP_POWER_NOW: - if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN) { + if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN) ret = -ENODEV; - break; - } - - val->intval = battery->rate_now * 1000; - /* - * When discharging, the current should be reported as a - * negative number as per the power supply class interface - * definition. - */ - if (psp == POWER_SUPPLY_PROP_CURRENT_NOW && - (battery->state & ACPI_BATTERY_STATE_DISCHARGING) && - acpi_battery_handle_discharging(battery) - == POWER_SUPPLY_STATUS_DISCHARGING) - val->intval = -val->intval; - + else + val->intval = battery->rate_now * 1000; break; case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN: -- 2.39.5

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