[Intel-gfx] [PATCH] drm/i915: Add DPI FIFO empty status check

Deepak M m.deepak at intel.com
Fri Dec 4 08:11:17 PST 2015

From: Gaurav K Singh <gaurav.k.singh at intel.com>

Before sending TURN ON packet,check the DPI
FIFO empty status.

v2: Change in commit message
    Checking for FIFO empty  only during TURN ON packet.

Signed-off-by: Gaurav K Singh <gaurav.k.singh at intel.com>
Signed-off-by: Deepak M <m.deepak at intel.com>
Got to know about the patch where they are removing this
DPI FIFO empty check while sending the SHUTDOWN packet.


According added the check and waiting for DPI FIFIO empty
only when TURN_ON packet is sent.

 drivers/gpu/drm/i915/intel_dsi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 170ae6f..495056f 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -222,6 +222,12 @@ static int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd, bool hs,
 		cmd |= DPI_LP_MODE;
+	mask = DPI_FIFO_EMPTY;
+	if ((cmd & TURN_ON) && wait_for((I915_READ(MIPI_GEN_FIFO_STAT(port)) &
+			mask) == mask, 50))
+		DRM_ERROR("Timeout waiting for DPI FIFO empty\n");
 	/* clear bit */

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