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* [PATCH] drm/i915/bxt: fix DDI PHY vswing scale value setting
@ 2015-06-04 15:01 Imre Deak
  2015-06-05  9:22 ` shuang.he
  2015-06-10 16:18 ` Matt Roper
  0 siblings, 2 replies; 5+ messages in thread
From: Imre Deak @ 2015-06-04 15:01 UTC (permalink / raw)
  To: intel-gfx

According to bspec the DDI PHY vswing scale value is "don't care" in
case the scale enable bit [27] is clear. But this doesn't seem to be
correct. The scale value seems to also matter if the scale mode bit
[26] is set. So both bit 26 and 27 depend on the value. Setting the
scale value to 0 while either bit is set results in a failed modeset on
HDMI (sink reports no signal).

After reset the scale value is 0x98, but according to the spec we have
to program it to 0x9a. So for consistency program it always to 0x9a
regardless of the scale enable bit.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 832e4e1..5246cfa 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -181,15 +181,15 @@ struct bxt_ddi_buf_trans {
  */
 static const struct bxt_ddi_buf_trans bxt_ddi_translations_dp[] = {
 					/* Idx	NT mV diff	db  */
-	{ 52,  0,    0, 128, true  },	/* 0:	400		0   */
-	{ 78,  0,    0, 85,  false },	/* 1:	400		3.5 */
-	{ 104, 0,    0, 64,  false },	/* 2:	400		6   */
-	{ 154, 0,    0, 43,  false },	/* 3:	400		9.5 */
-	{ 77,  0,    0, 128, false },	/* 4:	600		0   */
-	{ 116, 0,    0, 85,  false },	/* 5:	600		3.5 */
-	{ 154, 0,    0, 64,  false },	/* 6:	600		6   */
-	{ 102, 0,    0, 128, false },	/* 7:	800		0   */
-	{ 154, 0,    0, 85,  false },	/* 8:	800		3.5 */
+	{ 52,  0x9A, 0, 128, true  },	/* 0:	400		0   */
+	{ 78,  0x9A, 0, 85,  false },	/* 1:	400		3.5 */
+	{ 104, 0x9A, 0, 64,  false },	/* 2:	400		6   */
+	{ 154, 0x9A, 0, 43,  false },	/* 3:	400		9.5 */
+	{ 77,  0x9A, 0, 128, false },	/* 4:	600		0   */
+	{ 116, 0x9A, 0, 85,  false },	/* 5:	600		3.5 */
+	{ 154, 0x9A, 0, 64,  false },	/* 6:	600		6   */
+	{ 102, 0x9A, 0, 128, false },	/* 7:	800		0   */
+	{ 154, 0x9A, 0, 85,  false },	/* 8:	800		3.5 */
 	{ 154, 0x9A, 1, 128, false },  /* 9:	1200		0   */
 };
 
@@ -198,15 +198,15 @@ static const struct bxt_ddi_buf_trans bxt_ddi_translations_dp[] = {
  */
 static const struct bxt_ddi_buf_trans bxt_ddi_translations_hdmi[] = {
 					/* Idx	NT mV diff	db  */
-	{ 52,  0,    0, 128, false },	/* 0:	400		0   */
-	{ 52,  0,    0, 85,  false },	/* 1:	400		3.5 */
-	{ 52,  0,    0, 64,  false },	/* 2:	400		6   */
-	{ 42,  0,    0, 43,  false },	/* 3:	400		9.5 */
-	{ 77,  0,    0, 128, false },	/* 4:	600		0   */
-	{ 77,  0,    0, 85,  false },	/* 5:	600		3.5 */
-	{ 77,  0,    0, 64,  false },	/* 6:	600		6   */
-	{ 102, 0,    0, 128, false },	/* 7:	800		0   */
-	{ 102, 0,    0, 85,  false },	/* 8:	800		3.5 */
+	{ 52,  0x9A, 0, 128, false },	/* 0:	400		0   */
+	{ 52,  0x9A, 0, 85,  false },	/* 1:	400		3.5 */
+	{ 52,  0x9A, 0, 64,  false },	/* 2:	400		6   */
+	{ 42,  0x9A, 0, 43,  false },	/* 3:	400		9.5 */
+	{ 77,  0x9A, 0, 128, false },	/* 4:	600		0   */
+	{ 77,  0x9A, 0, 85,  false },	/* 5:	600		3.5 */
+	{ 77,  0x9A, 0, 64,  false },	/* 6:	600		6   */
+	{ 102, 0x9A, 0, 128, false },	/* 7:	800		0   */
+	{ 102, 0x9A, 0, 85,  false },	/* 8:	800		3.5 */
 	{ 154, 0x9A, 1, 128, true },	/* 9:	1200		0   */
 };
 
-- 
2.1.4

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^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2015-06-12  7:45 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-06-04 15:01 [PATCH] drm/i915/bxt: fix DDI PHY vswing scale value setting Imre Deak
2015-06-05  9:22 ` shuang.he
2015-06-10 16:18 ` Matt Roper
2015-06-11 10:34   ` Damien Lespiau
2015-06-12  7:48     ` Jani Nikula

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