[PATCH v3] efi: arm: defer probe of PCIe backed efifb on DT systems

Saravana Kannan saravanak at google.com
Fri Jan 10 09:06:05 PST 2020


On Thu, Jan 9, 2020 at 10:41 PM Ard Biesheuvel
<ard.biesheuvel at linaro.org> wrote:
>
> On Fri, 10 Jan 2020 at 04:01, Saravana Kannan <saravanak at google.com> wrote:
> >
> > From: Ard Biesheuvel <ardb at kernel.org>
> >
> > The new of_devlink support breaks PCIe probing on ARM platforms booting
> > via UEFI if the firmware exposes a EFI framebuffer that is backed by a
> > PCI device. The reason is that the probing order gets reversed,
> > resulting in a resource conflict on the framebuffer memory window when
> > the PCIe probes last, causing it to give up entirely.
> >
> > Given that we rely on PCI quirks to deal with EFI framebuffers that get
> > moved around in memory, we cannot simply drop the memory reservation, so
> > instead, let's use the device link infrastructure to register this
> > dependency, and force the probing to occur in the expected order.
> >
> > Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> > Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
> > Co-developed-by: Saravana Kannan <saravanak at google.com>
> > Signed-off-by: Saravana Kannan <saravanak at google.com>
> > Reviewed-by: Ard Biesheuvel <ardb at kernel.org>
> > ---
> >
> > v1 -> v2:
> > - Rewrote the device linking part to not depend on initcall ordering
> > v2 -> v3:
> > - Added const and check for CONFIG_PCI
> >
>
> Thanks. I've queued this version in efi/next for v5.6

Awesome, thanks!

-Saravana



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