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[PATCH v2] ACPI: video: Handle fetching EDID as ACPI_TYPE_PACKAGE

Gergo Koteles posted 1 patch 8 months, 3 weeks ago 
drivers/acpi/acpi_video.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
[PATCH v2] ACPI: video: Handle fetching EDID as ACPI_TYPE_PACKAGE
Posted by Gergo Koteles 8 months, 3 weeks ago 
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@vger.kernel.org
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@irl.hu>
---
Changes in v2:
 - Added comment
 - Improved commit message
 - Link to v1: https://lore.kernel.org/all/4cef341fdf7a0e877c50b502fc95ee8be28aa811.1743129387.git.soyer@irl.hu/

 drivers/acpi/acpi_video.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index efdadc74e3f4..103f29661576 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -649,6 +649,13 @@ acpi_video_device_EDID(struct acpi_video_device *device, void **edid, int length
 
 	obj = buffer.pointer;
 
+	/*
+	 * Some buggy implementations incorrectly return the EDID buffer in an ACPI package.
+	 * In this case, extract the buffer from the package.
+	 */
+	if (obj && obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 1)
+		obj = &obj->package.elements[0];
+
 	if (obj && obj->type == ACPI_TYPE_BUFFER) {
 		*edid = kmemdup(obj->buffer.pointer, obj->buffer.length, GFP_KERNEL);
 		ret = *edid ? obj->buffer.length : -ENOMEM;
@@ -658,7 +665,7 @@ acpi_video_device_EDID(struct acpi_video_device *device, void **edid, int length
 		ret = -EFAULT;
 	}
 
-	kfree(obj);
+	kfree(buffer.pointer);
 	return ret;
 }
 
-- 
2.49.0
Re: [PATCH v2] ACPI: video: Handle fetching EDID as ACPI_TYPE_PACKAGE
Posted by Rafael J. Wysocki 8 months, 2 weeks ago 
On Fri, Mar 28, 2025 at 10:09 PM Gergo Koteles <soyer@irl.hu> 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@vger.kernel.org
> 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@irl.hu>
> ---
> Changes in v2:
>  - Added comment
>  - Improved commit message
>  - Link to v1: https://lore.kernel.org/all/4cef341fdf7a0e877c50b502fc95ee8be28aa811.1743129387.git.soyer@irl.hu/

Hans, any concerns here?

>  drivers/acpi/acpi_video.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
> index efdadc74e3f4..103f29661576 100644
> --- a/drivers/acpi/acpi_video.c
> +++ b/drivers/acpi/acpi_video.c
> @@ -649,6 +649,13 @@ acpi_video_device_EDID(struct acpi_video_device *device, void **edid, int length
>
>         obj = buffer.pointer;
>
> +       /*
> +        * Some buggy implementations incorrectly return the EDID buffer in an ACPI package.
> +        * In this case, extract the buffer from the package.
> +        */
> +       if (obj && obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 1)
> +               obj = &obj->package.elements[0];
> +
>         if (obj && obj->type == ACPI_TYPE_BUFFER) {
>                 *edid = kmemdup(obj->buffer.pointer, obj->buffer.length, GFP_KERNEL);
>                 ret = *edid ? obj->buffer.length : -ENOMEM;
> @@ -658,7 +665,7 @@ acpi_video_device_EDID(struct acpi_video_device *device, void **edid, int length
>                 ret = -EFAULT;
>         }
>
> -       kfree(obj);
> +       kfree(buffer.pointer);
>         return ret;
>  }
>
> --
> 2.49.0
>
Re: [PATCH v2] ACPI: video: Handle fetching EDID as ACPI_TYPE_PACKAGE
Posted by Hans de Goede 8 months, 2 weeks ago 
Hi,

On 31-Mar-25 1:46 PM, Rafael J. Wysocki wrote:
> On Fri, Mar 28, 2025 at 10:09 PM Gergo Koteles <soyer@irl.hu> 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@vger.kernel.org
>> 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@irl.hu>
>> ---
>> Changes in v2:
>>  - Added comment
>>  - Improved commit message
>>  - Link to v1: https://lore.kernel.org/all/4cef341fdf7a0e877c50b502fc95ee8be28aa811.1743129387.git.soyer@irl.hu/
> 
> Hans, any concerns here?

No the patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans




> 
>>  drivers/acpi/acpi_video.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
>> index efdadc74e3f4..103f29661576 100644
>> --- a/drivers/acpi/acpi_video.c
>> +++ b/drivers/acpi/acpi_video.c
>> @@ -649,6 +649,13 @@ acpi_video_device_EDID(struct acpi_video_device *device, void **edid, int length
>>
>>         obj = buffer.pointer;
>>
>> +       /*
>> +        * Some buggy implementations incorrectly return the EDID buffer in an ACPI package.
>> +        * In this case, extract the buffer from the package.
>> +        */
>> +       if (obj && obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 1)
>> +               obj = &obj->package.elements[0];
>> +
>>         if (obj && obj->type == ACPI_TYPE_BUFFER) {
>>                 *edid = kmemdup(obj->buffer.pointer, obj->buffer.length, GFP_KERNEL);
>>                 ret = *edid ? obj->buffer.length : -ENOMEM;
>> @@ -658,7 +665,7 @@ acpi_video_device_EDID(struct acpi_video_device *device, void **edid, int length
>>                 ret = -EFAULT;
>>         }
>>
>> -       kfree(obj);
>> +       kfree(buffer.pointer);
>>         return ret;
>>  }
>>
>> --
>> 2.49.0
>>
>
Re: [PATCH v2] ACPI: video: Handle fetching EDID as ACPI_TYPE_PACKAGE
Posted by Rafael J. Wysocki 8 months, 2 weeks ago 
On Mon, Mar 31, 2025 at 3:04 PM Hans de Goede <hdegoede@redhat.com> 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@irl.hu> 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@vger.kernel.org
> >> 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@irl.hu>
> >> ---
> >> Changes in v2:
> >>  - Added comment
> >>  - Improved commit message
> >>  - Link to v1: https://lore.kernel.org/all/4cef341fdf7a0e877c50b502fc95ee8be28aa811.1743129387.git.soyer@irl.hu/
> >
> > Hans, any concerns here?
>
> No the patch looks good to me:
>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>

OK, applied as 6.15-rc material, thanks!
Re: [PATCH v2] ACPI: video: Handle fetching EDID as ACPI_TYPE_PACKAGE
Posted by Mario Limonciello 8 months, 2 weeks ago 
On 3/31/2025 08:23, Rafael J. Wysocki wrote:
> On Mon, Mar 31, 2025 at 3:04 PM Hans de Goede <hdegoede@redhat.com> 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@irl.hu> 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@vger.kernel.org
>>>> 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@irl.hu>
>>>> ---
>>>> Changes in v2:
>>>>   - Added comment
>>>>   - Improved commit message
>>>>   - Link to v1: https://lore.kernel.org/all/4cef341fdf7a0e877c50b502fc95ee8be28aa811.1743129387.git.soyer@irl.hu/
>>>
>>> Hans, any concerns here?
>>
>> No the patch looks good to me:
>>
>> Reviewed-by: Hans de Goede <hdegoede@redhat.com>
> 
> OK, applied as 6.15-rc material, thanks!

Sorry I'm a bit late to the party; but this looks good to me as well. 
Thanks Gergo for the solution!

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

Patchew 2.1-devel-b67e4c2

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