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

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Date:   Wed, 19 May 2021 17:53:05 +0800
From:   Aaron Ma <aaron.ma@...onical.com>
To:     lyude@...hat.com, jani.nikula@...el.com, airlied@...ux.ie,
        maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
        daniel@...ll.ch, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, aaron.ma@...onical.com
Subject: [PATCH] drm/i915: Force DPCD backlight mode for Samsung 16727 panel

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@...r.kernel.org # 5.11-
Signed-off-by: Aaron Ma <aaron.ma@...onical.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
-- 
2.25.1