[PATCH] drm: panel-backlight-quirks: Add ASUS ROG Flow X13 3840x2400 panel

[Hugo Sales <hugo@hsal.es>]

On an ASUS ROG Flow X13 GV301QH (BIOS 418) ATIF
QUERY_BACKLIGHT_TRANSFER_CHARACTERISTICS answers with a minimum input
signal of 12 and 49 curve points for the Sharp LQ134R1JW51 panel, and
amdgpu logs "Using custom brightness curve". With that minimum,
brightness 0 gives 4.7% duty

With the quirk, brightness 0 sends PWM 0 (read back from
amdgpu_current_backlight_pwm in debugfs). The panel stays lit, but much
dimmer than the old 4.7% floor. Its LED driver has a minimum of its own,
so 0 does not turn the backlight off

linux-hardware.org also lists this panel in a GV301QE. Match the ASUS
vendor and the panel, as the Framework 13 entries do, and let the
brightness reach the bottom of the PWM range

Signed-off-by: Hugo Sales <hugo@hsal.es>
---
I could only test this on a GV301QH. The entry matches any ASUS laptop
with this panel, and linux-hardware.org only lists it in ROG Flow X13s,
one of them a GV301QE. If you'd rather limit it to the GV301QH, I can
add a DMI_BOARD_NAME match in v2

 drivers/gpu/drm/drm_panel_backlight_quirks.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/drm/drm_panel_backlight_quirks.c
index 2d0238382ebd5..b60333e748741 100644
--- a/drivers/gpu/drm/drm_panel_backlight_quirks.c
+++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c
@@ -69,6 +69,14 @@ static const struct drm_get_panel_backlight_quirk drm_panel_min_backlight_quirks
 		.dmi_match_other.value = "Galileo",
 		.quirk = { .min_brightness = 1, },
 	},
+	/* ASUS ROG Flow X13 3840x2400 panel */
+	{
+		.dmi_match.field = DMI_SYS_VENDOR,
+		.dmi_match.value = "ASUSTeK COMPUTER INC.",
+		.ident.panel_id = drm_edid_encode_panel_id('S', 'H', 'P', 0x151b),
+		.ident.name = "LQ134R1JW51",
+		.quirk = { .min_brightness = 1, },
+	},
 	/* Have OLED Panels with brightness issue when last byte is 0/1 */
 	{
 		.dmi_match.field = DMI_SYS_VENDOR,
-- 
2.56.0