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Subject: Re: [PATCH] drm/edid: Add 6 bpc quirk for CPT panel in Asus UX303LA
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>, airlied@linux.ie
Cc:     daniel.vetter@intel.com, gustavo@padovan.org,
        seanpaul@chromium.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
References: <20180218085359.7817-1-kai.heng.feng@canonical.com>
From:   Mario Kleiner <mario.kleiner.de@gmail.com>
Message-ID: <d6a3afcb-91e5-dc91-7374-50f4864d7f2f@gmail.com>
Date:   Sun, 18 Feb 2018 13:17:25 +0100
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On 02/18/2018 09:53 AM, Kai-Heng Feng wrote:
> Similar to commit e10aec652f31 ("drm/edid: Add 6 bpc quirk for display
> AEO model 0."), the EDID reports "DFP 1.x compliant TMDS" but it support
> 6bpc instead of 8 bpc.
> 
> Hence, use 6 bpc quirk for this panel.
> 
> Fixes: 196f954e2509 ("drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown"")
> BugLink: https://bugs.launchpad.net/bugs/1749420
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>   drivers/gpu/drm/drm_edid.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index ddd537914575..d9c8d718e261 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -113,6 +113,9 @@ static const struct edid_quirk {
>   	/* AEO model 0 reports 8 bpc, but is a 6 bpc panel */
>   	{ "AEO", 0, EDID_QUIRK_FORCE_6BPC },
>   
> +	/* CPT panel of Asus UX303LA reports 8 bpc, but is a 6 bpc panel */
> +	{ "CPT", 0x17df, EDID_QUIRK_FORCE_6BPC },
> +
>   	/* Belinea 10 15 55 */
>   	{ "MAX", 1516, EDID_QUIRK_PREFER_LARGE_60 },
>   	{ "MAX", 0x77e, EDID_QUIRK_PREFER_LARGE_60 },
> 

Reviewed-by: Mario Kleiner <mario.kleiner.de@gmail.com>