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Commit ad9dc91b authored by Rodrigo Vivi's avatar Rodrigo Vivi Committed by Daniel Vetter
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drm/i915: Fix Sink CRC 



In some cases like when PSR just got enabled the panel need more vblank
times to calculate CRC. I figured that out with the new PSR test cases
facing some cases that I had a green screen but a blank CRC. Even with
2 vblank waits on kernel + 2 vblank waits on test case.

So let's give up to 6 vblank wait time. However we now check for
TEST_CRC_COUNT that shows when panel finished to calculate CRC and
has it ready.

v2: Jani pointed out attempts decrements was wrong and should never reach
the error condition. And Daniel pointed out that EIO is more appropriated than
EGAIN. Also I realized that I have to read test_crc_count after setting
test_sink

v3: Rebase and adding error message

Cc: Todd Previte <tprevite@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: default avatarTodd Previte <tprevite@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 6805b2a7

drivers/gpu/drm/i915/intel_dp.c

+17 −6
Original line number Diff line number Diff line
@@ -3807,21 +3807,32 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc) 
	struct drm_device *dev = intel_dig_port->base.base.dev;

	struct intel_crtc *intel_crtc =

		to_intel_crtc(intel_dig_port->base.base.crtc);

	u8 buf[1];

	u8 buf;

	int test_crc_count;

	int attempts = 6;



	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, buf) < 0)

	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf) < 0)

		return -EIO;



	if (!(buf[0] & DP_TEST_CRC_SUPPORTED))

	if (!(buf & DP_TEST_CRC_SUPPORTED))

		return -ENOTTY;



	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK,

			       DP_TEST_SINK_START) < 0)

		return -EIO;



	/* Wait 2 vblanks to be sure we will have the correct CRC value */

	intel_wait_for_vblank(dev, intel_crtc->pipe);

	drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf);

	test_crc_count = buf & DP_TEST_COUNT_MASK;



	do {

		drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf);

		intel_wait_for_vblank(dev, intel_crtc->pipe);

	} while (--attempts && (buf & DP_TEST_COUNT_MASK) == test_crc_count);



	if (attempts == 0) {

		DRM_ERROR("Panel is unable to calculate CRC after 6 vblanks\n");

		return -EIO;

	}



	if (drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_CRC_R_CR, crc, 6) < 0)

		return -EIO;

include/drm/drm_dp_helper.h

+3 −2
Original line number Diff line number Diff line
@@ -304,6 +304,7 @@ 


#define DP_TEST_SINK_MISC		    0x246

# define DP_TEST_CRC_SUPPORTED		    (1 << 5)

# define DP_TEST_COUNT_MASK		    0x7



#define DP_TEST_RESPONSE		    0x260

# define DP_TEST_ACK			    (1 << 0)