[PATCH 1/2] drm/i915: DPI FIFO empty check is not needed

[PATCH 1/2] drm/i915: DPI FIFO empty check is not needed

[Shobhit Kumar]

While sending DPI SHUTDOWN command, we cannot wait for FIFO empty as
pipes are not disabled at that time. In case of MIPI we disable port
first and send SHUTDOWN command while pipe is still running and FIFOs
will not be empty, causing spurious error log

Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
---
 drivers/gpu/drm/i915/intel_dsi_cmd.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dsi_cmd.c b/drivers/gpu/drm/i915/intel_dsi_cmd.c
index 3eeb21b..933c863 100644
--- a/drivers/gpu/drm/i915/intel_dsi_cmd.c
+++ b/drivers/gpu/drm/i915/intel_dsi_cmd.c
@@ -404,12 +404,6 @@ int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd, bool hs)
 	else
 		cmd |= DPI_LP_MODE;
 
-	/* DPI virtual channel?! */
-
-	mask = DPI_FIFO_EMPTY;
-	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == mask, 50))
-		DRM_ERROR("Timeout waiting for DPI FIFO empty.\n");
-
 	/* clear bit */
 	I915_WRITE(MIPI_INTR_STAT(pipe), SPL_PKT_SENT_INTERRUPT);
 
-- 
1.9.1

[PATCH 2/2] drm/i915: Update the DSI ULPS entry/exit sequence

[Shobhit Kumar]

We should keep DEVICE_READY bit set in the ULPS enter sequence. In
exit sequence also we should set DEVICE_READY, but thats causing
blankout for me. Also exit sequence is simplified as per hw team
recommendation.

This should fix -
[drm:intel_dsi_clear_device_ready] *ERROR* DSI LP not going Low

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80818
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
---
 drivers/gpu/drm/i915/intel_dsi.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index a6a1355..967a5b6 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -117,17 +117,18 @@ static void intel_dsi_device_ready(struct intel_encoder *encoder)
 	/* bandgap reset is needed after everytime we do power gate */
 	band_gap_reset(dev_priv);
 
+	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+	usleep_range(2500, 3000);
+
 	val = I915_READ(MIPI_PORT_CTRL(pipe));
 	I915_WRITE(MIPI_PORT_CTRL(pipe), val | LP_OUTPUT_HOLD);
 	usleep_range(1000, 1500);
-	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_EXIT);
-	usleep_range(2000, 2500);
-	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY);
-	usleep_range(2000, 2500);
-	I915_WRITE(MIPI_DEVICE_READY(pipe), 0x00);
-	usleep_range(2000, 2500);
+
+	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_EXIT);
+	usleep_range(2500, 3000);
+
 	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY);
-	usleep_range(2000, 2500);
+	usleep_range(2500, 3000);
 }
 
 static void intel_dsi_enable(struct intel_encoder *encoder)
@@ -271,23 +272,23 @@ static void intel_dsi_clear_device_ready(struct intel_encoder *encoder)
 
 	DRM_DEBUG_KMS("\n");
 
-	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_ENTER);
 	usleep_range(2000, 2500);
 
-	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_EXIT);
+	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_EXIT);
 	usleep_range(2000, 2500);
 
-	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_ENTER);
 	usleep_range(2000, 2500);
 
-	val = I915_READ(MIPI_PORT_CTRL(pipe));
-	I915_WRITE(MIPI_PORT_CTRL(pipe), val & ~LP_OUTPUT_HOLD);
-	usleep_range(1000, 1500);
-
 	if (wait_for(((I915_READ(MIPI_PORT_CTRL(pipe)) & AFE_LATCHOUT)
 					== 0x00000), 30))
 		DRM_ERROR("DSI LP not going Low\n");
 
+	val = I915_READ(MIPI_PORT_CTRL(pipe));
+	I915_WRITE(MIPI_PORT_CTRL(pipe), val & ~LP_OUTPUT_HOLD);
+	usleep_range(1000, 1500);
+
 	I915_WRITE(MIPI_DEVICE_READY(pipe), 0x00);
 	usleep_range(2000, 2500);
 
-- 
1.9.1

Re: [PATCH 2/2] drm/i915: Update the DSI ULPS entry/exit sequence

[Chris Wilson]

On Thu, Jul 03, 2014 at 04:35:41PM +0530, Shobhit Kumar wrote:
> We should keep DEVICE_READY bit set in the ULPS enter sequence. In
> exit sequence also we should set DEVICE_READY, but thats causing
> blankout for me. Also exit sequence is simplified as per hw team
> recommendation.
> 
> This should fix -
> [drm:intel_dsi_clear_device_ready] *ERROR* DSI LP not going Low
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80818
> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>

They silence that warning and appears to still work,
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH 2/2] drm/i915: Update the DSI ULPS entry/exit sequence

[Jani Nikula]

On Thu, 03 Jul 2014, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> On Thu, Jul 03, 2014 at 04:35:41PM +0530, Shobhit Kumar wrote:
>> We should keep DEVICE_READY bit set in the ULPS enter sequence. In
>> exit sequence also we should set DEVICE_READY, but thats causing
>> blankout for me. Also exit sequence is simplified as per hw team
>> recommendation.
>> 
>> This should fix -
>> [drm:intel_dsi_clear_device_ready] *ERROR* DSI LP not going Low
>> 
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80818
>> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
>
> They silence that warning and appears to still work,
> Tested-by: Chris Wilson <chris@chris-wilson.co.uk>

Pushed to -fixes, thanks for the patches and testing.

BR,
Jani.


> -Chris
>
> -- 
> Chris Wilson, Intel Open Source Technology Centre

-- 
Jani Nikula, Intel Open Source Technology Center