Re: [PATCH 11/11] video/aperture: Only remove sysfb on the default vga pci device

[Aaron Plattner]

On 1/11/23 8:58 AM, Javier Martinez Canillas wrote:
> Hello Daniel,
>
> On 1/11/23 16:41, Daniel Vetter wrote:
> > This fixes a regression introduced by 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 loosing 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 restor a working console.
>
> restore
>
> > 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 symptons. That bug is fixed now, see
>
> symptoms
>
> > https://bugzilla.kernel.org/show_bug.cgi?id=216331#c15
> >
> > 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.
>
> Maybe adding a Fixes: ee7a69aa38d8 tag here too ?
>
> > References: https://bugzilla.kernel.org/show_bug.cgi?id=216303#c28
> > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> > Cc: Aaron Plattner <aplattner@xxxxxxxxxx>
> > Cc: Javier Martinez Canillas <javierm@xxxxxxxxxx>
> > Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> > Cc: Helge Deller <deller@xxxxxx>
> > Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
> > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx> # 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 ba565515480d..a1821d369bb1 100644
> > --- a/drivers/video/aperture.c
> > +++ b/drivers/video/aperture.c
> > @@ -321,15 +321,16 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na
> >   
> >   	primary = pdev == vga_default_device();
> >   
> > +	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);
>
> Maybe mention in the commit message that you are doing this change, something like:
>
> "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"
>
> Patch looks good to me:
>
> Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>

Thanks Daniel and Javier!

I wasn't able to reproduce the original problem on my hybrid laptop 
since it refuses to boot with the console on an external display, but I 
was able to reproduce it by switching the configuration around: booting 
with i915.modeset=0 and with an experimental version of nvidia-drm that 
registers a framebuffer console. I verified that loading nvidia-drm 
breaks the efi-firmware framebuffer on Intel on Arch's 
linux-6.1.4-arch1-1 kernel and that applying this patch series fixes it. So

Tested-by: Aaron Plattner <aplattner@xxxxxxxxxx>

FWIW, the bug ought to be reproducible with i915.modeset=0 + any other 
drm driver that registers a framebuffer.

-- Aaron