On Thu, 9 May 2019 at 15:23, James Hilliard <james.hilliard1@xxxxxxxxx> wrote:
>
> On Tue, Apr 23, 2019 at 5:38 PM Ard Biesheuvel
> <ard.biesheuvel@xxxxxxxxxx> wrote:
> >
> > On Tue, 23 Apr 2019 at 17:01, James Hilliard <james.hilliard1@xxxxxxxxx> wrote:
> > >
> > > On Tue, Apr 23, 2019 at 4:44 PM Ard Biesheuvel
> > > <ard.biesheuvel@xxxxxxxxxx> wrote:
> > > >
> > > > Commit 38ac0287b7f4
> > > >
> > > > ("fbdev/efifb: Honour UEFI memory map attributes when mapping the FB")
> > > >
> > > > updated the EFI framebuffer code to use memory mappings for the linear
> > > > framebuffer that are permitted by the memory attributes described by the
> > > > EFI memory map for the particular region, if the framebuffer happens to
> > > > be covered by the EFI memory map (which is typically only the case for
> > > > framebuffers in shared memory). This is required since non-X86 systems
> > > > may require cacheable attributes for memory mappings that are shared
> > > > with other masters (such as GPUs), and this information cannot be
> > > > described by the Graphics Output Protocol (GOP) EFI protocol itself,
> > > > and so we rely on the EFI memory map for this.
> > > >
> > > > As reported by James, this breaks some x86 systems:
> > > >
> > > > [ 1.173368] efifb: probing for efifb
> > > > [ 1.173386] efifb: abort, cannot remap video memory 0x1d5000 @ 0xcf800000
> > > > [ 1.173395] Trying to free nonexistent resource <00000000cf800000-00000000cf9d4bff>
> > > > [ 1.173413] efi-framebuffer: probe of efi-framebuffer.0 failed with error -5
> > > >
> > > > The problem turns out to be that the memory map entry that describes the
> > > > framebuffer has no memory attributes listed at all, and so we end up with
> > > > a mem_flags value of 0x0.
> > > >
> > > > So work around this by ensuring that the memory map entry's attribute field
> > > > has a sane value before using it to mask the set of usable attributes.
> > > >
> > > > Reported-by: James Hilliard <james.hilliard1@xxxxxxxxx>
> > > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> > > > ---
> > > >
> > > > James, could you give this a try please? Thanks.
> > > I can confirm this fixes the regression on my system, thanks.
> >
> > Thanks James, I will add your tested-by.
> >
> > I forgot to include EFI_MEMORY_UC in the first mask, so I will respin
> > and resend.
> Is there an updated patch I should test?
No, apologies for the delay - I have updated the patch and will send
it upstream as a fix once I have confirmed that it doesn't cause any
regressions.
