Re: [PATCH] drm/i915: preserve other DP_TEST_SINK bits.

["Todd Previte" <tprevite@gmail.com>]

Hi Rodrigo,

Looks good. Only thing that needs to be removed is that extra blank line
between the last part of the function and the return statement. Otherwise...

Reviewed-by: Todd Previte <tprevite@gmail.com>

-----Original Message-----
From: Rodrigo Vivi [mailto:rodrigo.vivi@intel.com] 
Sent: Monday, September 29, 2014 3:30 PM
To: intel-gfx@lists.freedesktop.org
Cc: Rodrigo Vivi; Todd Previte
Subject: [PATCH] drm/i915: preserve other DP_TEST_SINK bits.

Sink crc was implemented based on dp 1.1 spec that had all TEST_SINK bits
reserved reading all 0s. But when reviewing my latest changes on sink crc
Todd warned me that on new specs we have other valid bits on this reg that
we might want to preserve.

Cc: Todd Previte <tprevite@gmail.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c
b/drivers/gpu/drm/i915/intel_dp.c index b8699b0..7d5fa2f 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3821,8 +3821,9 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8
*crc)
 	if (!(buf & DP_TEST_CRC_SUPPORTED))
 		return -ENOTTY;
 
+	drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK, &buf);
 	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK,
-			       DP_TEST_SINK_START) < 0)
+				buf | DP_TEST_SINK_START) < 0)
 		return -EIO;
 
 	drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf); @@
-3841,7 +3842,10 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8
*crc)
 	if (drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_CRC_R_CR, crc, 6) < 0)
 		return -EIO;
 
-	drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK, 0);
+	drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK, &buf);
+	drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK,
+			buf & ~DP_TEST_SINK_START);
+
 	return 0;
 }
 
--
1.9.3