drm/msm: fixup wait_for_completion_timeout handling
wait_for_completion_timeout return >= 0 but never negative so the check
logic looks inconsistent. Further the return value of
wait_for_completion_timeout was being passed up the call chain but the
x call sites as drm_dp_i2c_do_msg()/drm_dp_dpcd_access() check for < 0
thus timeout was being treated as success case.
<snip> drivers/gpu/drm/drm_dp_helper.c:drm_dp_i2c_do_msg()
mutex_lock(&aux->hw_mutex);
ret = aux->transfer(aux, msg);
mutex_unlock(&aux->hw_mutex);
if (ret < 0) {
<snip>
logic in edp_aux_transfer() seems incorrect as it could return 0 (timeout)
but checks of <= 0 to indicate error so the return probably should be
-ETIMEDOUT in case wait_for_completion_timeout returns 0 (timeout
occurred).
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/edp/edp_aux.c b/drivers/gpu/drm/msm/edp/edp_aux.c
index 208f9d4..5f77bf0 100644
--- a/drivers/gpu/drm/msm/edp/edp_aux.c
+++ b/drivers/gpu/drm/msm/edp/edp_aux.c
@@ -119,6 +119,7 @@
{
struct edp_aux *aux = to_edp_aux(drm_aux);
ssize_t ret;
+ unsigned long time_left;
bool native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);
bool read = msg->request & (DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
@@ -147,15 +148,16 @@
goto unlock_exit;
DBG("wait_for_completion");
- ret = wait_for_completion_timeout(&aux->msg_comp, 300);
- if (ret <= 0) {
+ time_left = wait_for_completion_timeout(&aux->msg_comp, 300);
+ if (!time_left) {
/*
* Clear GO and reset AUX channel
* to cancel the current transaction.
*/
edp_write(aux->base + REG_EDP_AUX_TRANS_CTRL, 0);
msm_edp_aux_ctrl(aux, 1);
- pr_err("%s: aux timeout, %zd\n", __func__, ret);
+ pr_err("%s: aux timeout, %lu\n", __func__, time_left);
+ ret = -ETIMEDOUT;
goto unlock_exit;
}
DBG("completion");