On Wed, Dec 4, 2019 at 10:27 AM Tomi Valkeinen tomi.valkeinen@ti.com wrote:
Hi Andrey,
On 19/06/2019 08:27, Andrey Smirnov wrote:
@@ -748,22 +748,19 @@ static int tc_set_video_mode(struct tc_data *tc,
static int tc_wait_link_training(struct tc_data *tc) {
u32 timeout = 1000; u32 value; int ret;do {udelay(1);tc_read(DP0_LTSTAT, &value);} while ((!(value & LT_LOOPDONE)) && (--timeout));if (timeout == 0) {
ret = tc_poll_timeout(tc, DP0_LTSTAT, LT_LOOPDONE,LT_LOOPDONE, 1, 1000);This seems to break DP at least with some monitors for me. I think it's just a timeout problem, as increasing the values helps.
Using ktime, I can see that during link training, the first call takes ~2ms, the second ~7ms. I think this worked before, as udelay(1) takes much longer than 1 us.
We have 1000us limit in a few other places too, which I don't see causing issues, but might need increasing too.
Also, 1us sleep_us may be a bit too small to be sane. If the loops take milliseconds, probably 100us or even more would make sense.
This didn't cause any issues with your display?
Hmm, not that I know of. Your reasoning makes sense, though. If increasing the timeout helps, I am all for it. And, yeah, I agree, this is probably not the only place that could use an increased timeout.
Thanks, Andrey Smirnov