Re: [PATCH] drm/amd/display: Add monitor patch for specific eDP

[Hamza Mahfooz <hamza.mahfooz@amd.com>]

On 2/27/24 13:18, Rodrigo Siqueira wrote:
> From: Ivan Lipski <ivlipski@amd.com>
> 
> [WHY]
> Some eDP panels's ext caps don't write initial value cause the value of
> dpcd_addr(0x317) is random.  It means that sometimes the eDP will
> clarify it is OLED, miniLED...etc cause the backlight control interface
> is incorrect.
> 
> [HOW]
> Add a new panel patch to remove sink ext caps(HDR,OLED...etc)

I wonder if it would make sense to turn this into a DPCD qurik (see
drivers/gpu/drm/display/drm_dp_helper.c). Since, it is rather unsettling
that we have so many panel quirks in our driver.

> 
> Cc: stable@vger.kernel.org # 6.5.x
> Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
> Cc: Tsung-hua Lin <tsung-hua.lin@amd.com>
> Cc: Chris Chi <moukong.chi@amd.com>
> Cc: Harry Wentland <Harry.Wentland@amd.com>
> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
> Reviewed-by: Sun peng Li <sunpeng.li@amd.com>
> Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
> Signed-off-by: Ivan Lipski <ivlipski@amd.com>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> index d9a482908380..764dc3ffd91b 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> @@ -63,6 +63,12 @@ static void apply_edid_quirks(struct edid *edid, struct dc_edid_caps *edid_caps)
>   		DRM_DEBUG_DRIVER("Disabling FAMS on monitor with panel id %X\n", panel_id);
>   		edid_caps->panel_patch.disable_fams = true;
>   		break;
> +	/* Workaround for some monitors that do not clear DPCD 0x317 if FreeSync is unsupported */
> +	case drm_edid_encode_panel_id('A', 'U', 'O', 0xA7AB):
> +	case drm_edid_encode_panel_id('A', 'U', 'O', 0xE69B):
> +		DRM_DEBUG_DRIVER("Clearing DPCD 0x317 on monitor with panel id %X\n", panel_id);
> +		edid_caps->panel_patch.remove_sink_ext_caps = true;
> +		break;
>   	default:
>   		return;
>   	}
-- 
Hamza