[Intel-gfx] [PATCH v2 8/9] drm/i915/dp: Improve intel_dp_aux_is_busy()

[José Roberto de Souza]

- Doing earlier return when not busy
- using u32 instead of uint32_t
- counting from 3 to 0 as it is is the most common in the driver
- using DRM_WARN() instead of WARN()
- adding aux port name to the debug message
- nuking last_status, it is one static variable to all DP ports
also 2 different aux transactions with the same message size would
have the same ch_ctl value, if really desired to reduce the number
of debug messages it should be implemented a per aux ch last_status
- no need to sleep in the last try
- sleeping for 1 aux ch transaction time

Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
---

New patch in this series.

 drivers/gpu/drm/i915/intel_dp.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a11465c62950..258e23961456 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1068,28 +1068,21 @@ static bool intel_dp_aux_is_busy(struct intel_dp *intel_dp)
 	struct drm_i915_private *dev_priv =
 			to_i915(intel_dig_port->base.base.dev);
 	i915_reg_t ch_ctl;
-	uint32_t status;
-	int try;
+	u32 status;
+	unsigned int try;
 
 	ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
 
-	for (try = 0; try < 3; try++) {
+	for (try = 3; try; try--) {
 		status = I915_READ_NOTRACE(ch_ctl);
 		if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
-			break;
-		msleep(1);
+			return false;
+		if (try > 1)
+			usleep_range(400, 500);
 	}
 
-	if (try == 3) {
-		static u32 last_status = -1;
-		const u32 status = I915_READ(ch_ctl);
-
-		if (status != last_status) {
-			WARN(1, "dp_aux_ch not started status 0x%08x\n",
-			     status);
-			last_status = status;
-		}
-	}
+	DRM_WARN("DP aux %c is busy 0x%08x\n",
+		 aux_ch_name(intel_dp->aux_ch), status);
 
 	return true;
 }
-- 
2.17.0