Commit 4373f0f2 authored by Paulo Zanoni's avatar Paulo Zanoni Committed by Daniel Vetter
Browse files

drm/i915: disable IPS while getting the sink CRCs 



This commit is the "sink CRC" version of:

commit 8c740dce
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date:   Fri Oct 17 18:42:03 2014 -0300
    drm/i915: disable IPS while getting the pipe CRCs.

For some unknown reason, when IPS gets enabled, the sink CRC changes.
Since hsw_enable_ips() doesn't really guarantee to enable IPS (it
depends on package C-states), we can't really predict if IPS is
enabled or disabled while running our CRC tests, so let's just
completely disable IPS while sink CRCs are being used.

If we find a way to make IPS not change the pipe CRC result, we may
want to fix IPS and then revert this patch (and 8c740dce too). While
this doesn't happen, let's merge this patch, so the IGT tests relying
on sink CRCs can work properly.

This was discovered while developing a new IGT test, which will
probably be called kms_frontbuffer_tracking.

Testcase: igt/kms_frontbuffer_tracking (not on upstream IGT yet)
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 5e3daaca

drivers/gpu/drm/i915/intel_dp.c

+45 −21
Original line number Diff line number Diff line
@@ -4041,46 +4041,70 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc) 
	u8 buf;

	int test_crc_count;

	int attempts = 6;

	int ret = 0;



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

		return -EIO;

	hsw_disable_ips(intel_crtc);



	if (!(buf & DP_TEST_CRC_SUPPORTED))

		return -ENOTTY;

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

		ret = -EIO;

		goto out;

	}



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

		return -EIO;

	if (!(buf & DP_TEST_CRC_SUPPORTED)) {

		ret = -ENOTTY;

		goto out;

	}



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

		ret = -EIO;

		goto out;

	}



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

				buf | DP_TEST_SINK_START) < 0)

		return -EIO;

				buf | DP_TEST_SINK_START) < 0) {

		ret = -EIO;

		goto out;

	}



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

		ret = -EIO;

		goto out;

	}



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

		return -EIO;

	test_crc_count = buf & DP_TEST_COUNT_MASK;



	do {

		if (drm_dp_dpcd_readb(&intel_dp->aux,

				      DP_TEST_SINK_MISC, &buf) < 0)

			return -EIO;

				      DP_TEST_SINK_MISC, &buf) < 0) {

			ret = -EIO;

			goto out;

		}

		intel_wait_for_vblank(dev, intel_crtc->pipe);

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



	if (attempts == 0) {

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

		return -ETIMEDOUT;

		ret = -ETIMEDOUT;

		goto out;

	}



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

		return -EIO;

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

		ret = -EIO;

		goto out;

	}



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

		return -EIO;

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

		ret = -EIO;

		goto out;

	}

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

			       buf & ~DP_TEST_SINK_START) < 0)

		return -EIO;



	return 0;

			       buf & ~DP_TEST_SINK_START) < 0) {

		ret = -EIO;

		goto out;

	}

out:

	hsw_enable_ips(intel_crtc);

	return ret;

}



static bool

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