[PATCH] drm/i915: Force DPCD backlight mode for Samsung 16727 panel

[Aaron Ma]

Hi Greg:

Could this patch get a chance to be applied on stable kernel?
It only for 5.11- kernel, not for Linus' tree.

Thanks,
Aaron

On 5/20/21 12:27 AM, Lyude Paul wrote:
> Seems reasonable to me:
>
> Reviewed-by: Lyude Paul <lyude at redhat.com>
>
> On Wed, 2021-05-19 at 17:53 +0800, Aaron Ma wrote:
>> Another Samsung OLED panel needs DPCD to get control of backlight.
>> Kernel 5.12+ support the backlight via:
>> commit: <4a8d79901d5b> ("drm/i915/dp: Enable Intel's HDR backlight interface
>> (only SDR for now)")
>> Only make backlight work on lower versions of kernel.
>>
>> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3474
>> Cc: stable at vger.kernel.org # 5.11-
>> Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
>> ---
>>   drivers/gpu/drm/drm_dp_helper.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
>> index 5bd0934004e3..7b91d8a76cd6 100644
>> --- a/drivers/gpu/drm/drm_dp_helper.c
>> +++ b/drivers/gpu/drm/drm_dp_helper.c
>> @@ -1960,6 +1960,7 @@ static const struct edid_quirk edid_quirk_list[] = {
>>          { MFG(0x4d, 0x10), PROD_ID(0xe6, 0x14),
>> BIT(DP_QUIRK_FORCE_DPCD_BACKLIGHT) },
>>          { MFG(0x4c, 0x83), PROD_ID(0x47, 0x41),
>> BIT(DP_QUIRK_FORCE_DPCD_BACKLIGHT) },
>>          { MFG(0x09, 0xe5), PROD_ID(0xde, 0x08),
>> BIT(DP_QUIRK_FORCE_DPCD_BACKLIGHT) },
>> +       { MFG(0x4c, 0x83), PROD_ID(0x57, 0x41),
>> BIT(DP_QUIRK_FORCE_DPCD_BACKLIGHT) },
>>   };
>>   
>>   #undef MFG