[PATCH 1/2] drm/radeon: implement ACPI VFCT vbios fetch (v2)

[Alex Deucher]

Adding Matthew in case he as any ideas.

On Thu, Aug 16, 2012 at 3:51 PM, Alex Deucher <alexdeucher at gmail.com> wrote:
> On Thu, Aug 16, 2012 at 3:40 PM, David Lamparter <equinox at diac24.net> wrote:
>> On Thu, Aug 16, 2012 at 03:13:46PM -0400, alexdeucher at gmail.com wrote:
>>> From: David L <equinox-freedesktopbugs at diac24.net>
>> From: David Lamparter <equinox at diac24.net>
>>
>> There are still two rough edges left in here, I didn't get around to
>> clean it up, other stuff came up -- sorry...
>>
>>> This is required for pure UEFI systems.  The vbios is stored
>>> in ACPI rather than at the legacy vga location.
>>>
>>> Fixes:
>>> https://bugs.freedesktop.org/show_bug.cgi?id=26891
>>>
>>> V2: fix #ifdefs as per Greg's comments
>>>
>>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>>> Cc: stable at vger.kernel.org
>>> ---
>> [...]
>>> +     struct acpi_table_header *hdr;
>>> +     /* acpi_get_table_with_size is not exported :( */
>>> +     acpi_size tbl_size = 0x7fffffff;
>>
>> I was using acpi_get_table_with_size, but that needs an export, with
>> 0x7fffffff all the tests below are kinda useless because they always
>> succeed.  I think it'd be useful to keep the length checks in case some
>> vendor breaks their ACPI tables, so this needs an EXPORT_SYMBOL.
>
> I guess we could leave it as is for now for -fixes and then switch it
> use use the new exported symbol for -next?  Is it ok to export a new
> symbol for -fixes?
>
>>
>>> +     UEFI_ACPI_VFCT *vfct;
>>> +     GOP_VBIOS_CONTENT *vbios;
>>> +     VFCT_IMAGE_HEADER *vhdr;
>>> +
>>> +     if (!ACPI_SUCCESS(acpi_get_table("VFCT", 1, &hdr)))
>>> +             return false;
>>> +     if (tbl_size < sizeof(UEFI_ACPI_VFCT)) {
>>> +             DRM_ERROR("ACPI VFCT table present but broken (too short #1)\n");
>>> +             goto out_unmap;
>>> +     }
>>> +
>>> +     vfct = (UEFI_ACPI_VFCT *)hdr;
>>> +     if (vfct->VBIOSImageOffset + sizeof(VFCT_IMAGE_HEADER) > tbl_size) {
>>> +             DRM_ERROR("ACPI VFCT table present but broken (too short #2)\n");
>>> +             goto out_unmap;
>>> +     }
>>> +
>>> +     vbios = (GOP_VBIOS_CONTENT *)((char *)hdr + vfct->VBIOSImageOffset);
>>> +     vhdr = &vbios->VbiosHeader;
>>> +     DRM_INFO("ACPI VFCT contains a BIOS for %02x:%02x.%d %04x:%04x, size %d\n",
>>> +                     vhdr->PCIBus, vhdr->PCIDevice, vhdr->PCIFunction,
>>> +                     vhdr->VendorID, vhdr->DeviceID, vhdr->ImageLength);
>>> +
>>> +     if (vhdr->PCIBus != rdev->pdev->bus->number ||
>>> +         vhdr->PCIDevice != PCI_SLOT(rdev->pdev->devfn) ||
>>> +         vhdr->PCIFunction != PCI_FUNC(rdev->pdev->devfn) ||
>>> +         vhdr->VendorID != rdev->pdev->vendor ||
>>> +         vhdr->DeviceID != rdev->pdev->device) {
>>> +             DRM_INFO("ACPI VFCT table is not for this card\n");
>>> +             goto out_unmap;
>>> +     };
>>> +
>>> +     if (vfct->VBIOSImageOffset + sizeof(VFCT_IMAGE_HEADER) + vhdr->ImageLength > tbl_size) {
>>> +             DRM_ERROR("ACPI VFCT image truncated\n");
>>> +             goto out_unmap;
>>> +     }
>>> +
>>> +     rdev->bios = kmemdup(&vbios->VbiosContent, vhdr->ImageLength, GFP_KERNEL);
>>> +     ret = !!rdev->bios;
>>> +
>>> +out_unmap:
>>> +     /* uh, no idea what to do here... */
>>
>> So, er, I had no clue how to clean up the return value of acpi_get_table
>> - does this actually need to be cleaned up?  Or do you just get a
>> pointer straight to the "real" ACPI table?
>
> Not sure on that.  Anyone know more about the acpi code?
>
> Alex