[Intel-gfx] [PATCH 1/2] drm/dp: Add DP_DPCD_QUIRK_NO_SINK_COUNT

[Ville Syrjälä]

On Tue, May 28, 2019 at 05:06:49PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> CH7511 eDP->LVDS bridge doesn't seem to set SINK_COUNT properly
> causing i915 to detect it as disconnected. Add a quirk to ignore
> SINK_COUNT on these devices.
> 
> Cc: David S. <david at majinbuu.com>
> Cc: Peteris Rudzusiks <peteris.rudzusiks at gmail.com>
> Tested-by: Peteris Rudzusiks <peteris.rudzusiks at gmail.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105406
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Pushed patch 1 to drm-misc-next with Jani's irc ack.

I thought of pushing the i915 patch drm-misc-next too, but then
thought better of it due to the current i915 code churn. I'll
just wait for a backmerge instead.

> ---
>  drivers/gpu/drm/drm_dp_helper.c | 4 +++-
>  include/drm/drm_dp_helper.h     | 7 +++++++
>  2 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index e6af758a7d22..0b994d083a89 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -1280,7 +1280,9 @@ static const struct dpcd_quirk dpcd_quirk_list[] = {
>  	/* LG LP140WF6-SPM1 eDP panel */
>  	{ OUI(0x00, 0x22, 0xb9), DEVICE_ID('s', 'i', 'v', 'a', 'r', 'T'), false, BIT(DP_DPCD_QUIRK_CONSTANT_N) },
>  	/* Apple panels need some additional handling to support PSR */
> -	{ OUI(0x00, 0x10, 0xfa), DEVICE_ID_ANY, false, BIT(DP_DPCD_QUIRK_NO_PSR) }
> +	{ OUI(0x00, 0x10, 0xfa), DEVICE_ID_ANY, false, BIT(DP_DPCD_QUIRK_NO_PSR) },
> +	/* CH7511 seems to leave SINK_COUNT zeroed */
> +	{ OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) },
>  };
>  
>  #undef OUI
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 3fc534ee8174..7e52eb81284a 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1414,6 +1414,13 @@ enum drm_dp_quirk {
>  	 * driver still need to implement proper handling for such device.
>  	 */
>  	DP_DPCD_QUIRK_NO_PSR,
> +	/**
> +	 * @DP_DPCD_QUIRK_NO_SINK_COUNT:
> +	 *
> +	 * The device does not set SINK_COUNT to a non-zero value.
> +	 * The driver should ignore SINK_COUNT during detection.
> +	 */
> +	DP_DPCD_QUIRK_NO_SINK_COUNT,
>  };
>  
>  /**
> -- 
> 2.21.0

-- 
Ville Syrjälä
Intel