On Wed, Jan 11, 2023 at 05:20:00PM +0100, Thomas Zimmermann wrote:
> Hi
>
> Am 11.01.23 um 16:41 schrieb Daniel Vetter:
> > 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.
> >
> > 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
> > 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.
> >
> > 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();
> > +
>
> There's another sysfb_disable() in aperture_remove_conflicting_devices()
> without the branch but with a long comment. I find this slightly confusing.
>
> I'd rather add a branched sysfb_disable() plus the comment to
> aperture_detach_devices(). And then add a 'primary' parameter to
> aperture_detach_devices(). In aperture_remove_conflicting_devices() the
> parameter would be unconditionally true.
Yeah I was on the fence, but should be easy to redo with all the prep work
out of the way. It does mean we call sysfb_disable once for every bar, but
that shouldn't matter in any reasonable case :-)
-Daniel
>
> Best regards
> Thomas
>
> > 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)
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Ivo Totev
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
