On Mon, Mar 31, 2025 at 3:04 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> Hi,
>
> On 31-Mar-25 1:46 PM, Rafael J. Wysocki wrote:
> > On Fri, Mar 28, 2025 at 10:09 PM Gergo Koteles <soyer@xxxxxx> wrote:
> >>
> >> The _DDC method should return a buffer, or an integer in case of an error.
> >> But some Lenovo laptops incorrectly return EDID as buffer in ACPI package.
> >>
> >> Calling _DDC generates this ACPI Warning:
> >> ACPI Warning: \_SB.PCI0.GP17.VGA.LCD._DDC: Return type mismatch - \
> >> found Package, expected Integer/Buffer (20240827/nspredef-254)
> >>
> >> Use the first element of the package to get the EDID buffer.
> >>
> >> The DSDT:
> >>
> >> Name (AUOP, Package (0x01)
> >> {
> >> Buffer (0x80)
> >> {
> >> ...
> >> }
> >> })
> >>
> >> ...
> >>
> >> Method (_DDC, 1, NotSerialized) // _DDC: Display Data Current
> >> {
> >> If ((PAID == AUID))
> >> {
> >> Return (AUOP) /* \_SB_.PCI0.GP17.VGA_.LCD_.AUOP */
> >> }
> >> ElseIf ((PAID == IVID))
> >> {
> >> Return (IVOP) /* \_SB_.PCI0.GP17.VGA_.LCD_.IVOP */
> >> }
> >> ElseIf ((PAID == BOID))
> >> {
> >> Return (BOEP) /* \_SB_.PCI0.GP17.VGA_.LCD_.BOEP */
> >> }
> >> ElseIf ((PAID == SAID))
> >> {
> >> Return (SUNG) /* \_SB_.PCI0.GP17.VGA_.LCD_.SUNG */
> >> }
> >>
> >> Return (Zero)
> >> }
> >>
> >> Link: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/Apx_B_Video_Extensions/output-device-specific-methods.html#ddc-return-the-edid-for-this-device
> >> Cc: stable@xxxxxxxxxxxxxxx
> >> Fixes: c6a837088bed ("drm/amd/display: Fetch the EDID from _DDC if available for eDP")
> >> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4085
> >> Signed-off-by: Gergo Koteles <soyer@xxxxxx>
> >> ---
> >> Changes in v2:
> >> - Added comment
> >> - Improved commit message
> >> - Link to v1: https://lore.kernel.org/all/4cef341fdf7a0e877c50b502fc95ee8be28aa811.1743129387.git.soyer@xxxxxx/
> >
> > Hans, any concerns here?
>
> No the patch looks good to me:
>
> Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
OK, applied as 6.15-rc material, thanks!
