[PATCH 3/3] drm: add LG eDP panel to quirk database

Lee, Shawn C shawn.c.lee at intel.com
Mon Sep 10 08:30:14 UTC 2018

The N value was computed by kernel driver that based on synchronous clock
mode. But only specific N value (0x8000) would be acceptable for
LG LP140WF6-SPM1 eDP panel which is running at asynchronous clock mode.
With the other N value, Tcon will enter BITS mode and display black screen.
Add this panel into quirk database and give particular N value when
calculate M/N divider.

Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Cooper Chiou <cooper.chiou at intel.com>
Cc: Matt Atwood <matthew.s.atwood at intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Cc: Clint Taylor <clinton.a.taylor at intel.com>
Signed-off-by: Lee, Shawn C <shawn.c.lee at intel.com>
 drivers/gpu/drm/drm_dp_helper.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index d0c1250975ab..0ef7c43a9025 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1270,6 +1270,8 @@ struct dpcd_quirk {
 static const struct dpcd_quirk dpcd_quirk_list[] = {
 	/* Analogix 7737 needs reduced M and N at HBR2 link rates */
 	{ OUI(0x00, 0x22, 0xb9), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_CONSTANT_N) },
+	/* LG LP140WF6-SPM1 eDP panel */
+	{ OUI(0x00, 0x22, 0xb9), DEVICE_ID('s', 'i', 'v', 'a', 'r', 'T'), false, BIT(DP_DPCD_QUIRK_CONSTANT_N) },
 #undef OUI

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