6.12-stable review patch. If anyone has any objections, please let me know.
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From: Ilpo Järvinen ilpo.jarvinen@linux.intel.com
commit 7507eb3e7bfac7c3baef8dd377fdf5871eefd42b upstream.
Commit 1db806ec06b7 ("PCI/ASPM: Save parent L1SS config in pci_save_aspm_l1ss_state()") aimed to perform L1SS config save for both the Upstream Port and its upstream bridge when handling an Upstream Port, which matches what the L1SS restore side does. However, parent->state_saved can be set true at an earlier time when the upstream bridge saved other parts of its state. Then later when attempting to save the L1SS config while handling the Upstream Port, parent->state_saved is true in pci_save_aspm_l1ss_state() resulting in early return and skipping saving bridge's L1SS config because it is assumed to be already saved. Later on restore, junk is written into L1SS config which causes issues with some devices.
Remove parent->state_saved check and unconditionally save L1SS config also for the upstream bridge from an Upstream Port which ought to be harmless from correctness point of view. With the Upstream Port check now present, saving the L1SS config more than once for the bridge is no longer a problem (unlike when the parent->state_saved check got introduced into the fix during its development).
Link: https://lore.kernel.org/r/20250131152913.2507-1-ilpo.jarvinen@linux.intel.co... Fixes: 1db806ec06b7 ("PCI/ASPM: Save parent L1SS config in pci_save_aspm_l1ss_state()") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219731 Reported-by: Niklāvs Koļesņikovs pinkflames.linux@gmail.com Reported by: Rafael J. Wysocki rafael@kernel.org Closes: https://lore.kernel.org/r/CAJZ5v0iKmynOQ5vKSQbg1J_FmavwZE-nRONovOZ0mpMVauheW... Reported-by: Paul Menzel pmenzel@molgen.mpg.de Closes: https://lore.kernel.org/r/d7246feb-4f3f-4d0c-bb64-89566b170671@molgen.mpg.de Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Tested-by: Niklāvs Koļesņikovs pinkflames.linux@gmail.com Tested-by: Paul Menzel pmenzel@molgen.mpg.de # Dell XPS 13 9360 Cc: Brian Norris briannorris@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/pcie/aspm.c | 3 --- 1 file changed, 3 deletions(-)
--- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -108,9 +108,6 @@ void pci_save_aspm_l1ss_state(struct pci pci_read_config_dword(pdev, pdev->l1ss + PCI_L1SS_CTL2, cap++); pci_read_config_dword(pdev, pdev->l1ss + PCI_L1SS_CTL1, cap++);
- if (parent->state_saved) - return; - /* * Save parent's L1 substate configuration so we have it for * pci_restore_aspm_l1ss_state(pdev) to restore.