From: Daniel Vetter daniel.vetter@ffwll.ch
Instead of calling aperture_remove_conflicting_devices() to remove the conflicting devices, just call to aperture_detach_devices() to detach the device that matches the same PCI BAR / aperture range. Since the former is just a wrapper of the latter plus a sysfb_disable() call, and now that's done in this function but only for the primary devices.
This fixes a regression introduced by commit ee7a69aa38d8 ("fbdev: Disable sysfb device registration when removing conflicting FBs"), where we remove the sysfb when loading a driver for an unrelated pci device, resulting in the user losing their efifb console or similar.
Note that in practice this only is a problem with the nvidia blob, because that's the only gpu driver people might install which does not come with an fbdev driver of it's own. For everyone else the real gpu driver will restore a working console.
Also note that in the referenced bug there's confusion that this same bug also happens on amdgpu. But that was just another amdgpu specific regression, which just happened to happen at roughly the same time and with the same user-observable symptoms. That bug is fixed now, see https://bugzilla.kernel.org/show_bug.cgi?id=216331#c15
Note that we should not have any such issues on non-pci multi-gpu issues, because I could only find two such cases: - SoC with some external panel over spi or similar. These panel drivers do not use drm_aperture_remove_conflicting_framebuffers(), so no problem. - vga+mga, which is a direct console driver and entirely bypasses all this.
For the above reasons the cc: stable is just notionally, this patch will need a backport and that's up to nvidia if they care enough.
v2: - Explain a bit better why other multi-gpu that aren't pci shouldn't have any issues with making all this fully pci specific.
v3 - polish commit message (Javier)
v4: - Fix commit message style (i.e., commit 1234 ("...")) - fix Daniel's S-o-b address
v5: - add back an S-o-b tag with Daniel's Intel address
Fixes: ee7a69aa38d8 ("fbdev: Disable sysfb device registration when removing conflicting FBs") Tested-by: Aaron Plattner aplattner@nvidia.com Reviewed-by: Javier Martinez Canillas javierm@redhat.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=216303#c28 Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Aaron Plattner aplattner@nvidia.com Cc: Javier Martinez Canillas javierm@redhat.com Cc: Thomas Zimmermann tzimmermann@suse.de Cc: Helge Deller deller@gmx.de Cc: Sam Ravnborg sam@ravnborg.org Cc: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org # v5.19+ (if someone else does the backport) --- drivers/video/aperture.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c index 1356f0e88241..e4091688b5eb 100644 --- a/drivers/video/aperture.c +++ b/drivers/video/aperture.c @@ -322,15 +322,16 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na if (pdev == vga_default_device()) primary = true;
+ if (primary) + sysfb_disable(); + for (bar = 0; bar < PCI_STD_NUM_BARS; ++bar) { if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) continue;
base = pci_resource_start(pdev, bar); size = pci_resource_len(pdev, bar); - ret = aperture_remove_conflicting_devices(base, size, name); - if (ret) - return ret; + aperture_detach_devices(base, size); }
if (primary) {