[PATCH 02/10] drm/i915: Add counters in the drm_dp_aux struct for I2C NACKs and DEFERs

[Todd Previte]

These counters are used for Displayort complinace testing to detect error conditions
when executing certain compliance tests. Currently these are used in the EDID tests
to determine if the video mode needs to be set to the preferred mode or the failsafe
mode.

Cc: dri-devel at lists.freedesktop.org
Signed-off-by: Todd Previte <tprevite at gmail.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 2 ++
 include/drm/drm_dp_helper.h     | 1 +
 2 files changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 08e33b8..8353051 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -654,10 +654,12 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 
 		case DP_AUX_I2C_REPLY_NACK:
 			DRM_DEBUG_KMS("I2C nack\n");
+			aux->i2c_nack_count++;
 			return -EREMOTEIO;
 
 		case DP_AUX_I2C_REPLY_DEFER:
 			DRM_DEBUG_KMS("I2C defer\n");
+			aux->i2c_defer_count++;
 			usleep_range(400, 500);
 			continue;
 
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 8edeed0..45f3ee8 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -551,6 +551,7 @@ struct drm_dp_aux {
 	struct mutex hw_mutex;
 	ssize_t (*transfer)(struct drm_dp_aux *aux,
 			    struct drm_dp_aux_msg *msg);
+	uint8_t i2c_nack_count, i2c_defer_count;
 };
 
 ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset,
-- 
1.9.1