All three patches are:
Reviewed-by: Simon Farnsworth simon.farnsworth@onelan.com
I'd consider making the upper limit of AUX_RETRY_INTERVAL a define as well, but that's just nit-picking and not worth respinning the patches.
Simon
On Wednesday 26 Aug 2015 22:55:07 ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
To help with debugging i2c-over-aux issues, add a module parameter than can be used to tweak the assumed i2c bus speed, and thus the maximum number of retries we will do for each aux message.
Cc: Simon Farnsworth simon.farnsworth@onelan.com Cc: moosotc@gmail.com Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/drm_dp_helper.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 23b9fcc..ee5cd86 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -497,6 +497,15 @@ static int drm_dp_i2c_retry_count(const struct drm_dp_aux_msg *msg, }
/*
- FIXME currently assumes 10 kHz as some real world devices seem
- to require it. We should query/set the speed via DPCD if supported.
- */
+static int dp_aux_i2c_speed_khz __read_mostly = 10; +module_param_unsafe(dp_aux_i2c_speed_khz, int, 0644); +MODULE_PARM_DESC(dp_aux_i2c_speed_khz,
"Assumed speed of the i2c bus in kHz, (1-400, default 10)");+/*
- Transfer a single I2C-over-AUX message and handle various error
conditions, * retrying the transaction as appropriate. It is assumed that the * aux->transfer function does not modify anything in the msg other than the @@ -514,10 +523,8 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) * before giving up the AUX transaction. * * We also try to account for the i2c bus speed.
* FIXME currently assumes 10 kHz as some real world devices seem* to require it. We should query/set the speed via DPCD if supported.- int max_retries = max(7, drm_dp_i2c_retry_count(msg, 10));
- int max_retries = max(7, drm_dp_i2c_retry_count(msg,
dp_aux_i2c_speed_khz));
for (retry = 0, defer_i2c = 0; retry < (max_retries + defer_i2c);
retry++)
{ mutex_lock(&aux->hw_mutex);