Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-19 Thread Nathan Ciobanu
On Thu, Jul 19, 2018 at 10:01:41AM -0700, Rodrigo Vivi wrote: > On Tue, Jul 17, 2018 at 06:05:51PM -0700, Nathan Ciobanu wrote: > > On Tue, Jul 17, 2018 at 03:21:17PM -0700, Dhinakaran Pandiyan wrote: > > > On Mon, 2018-07-16 at 16:51 -0700, Marc Herbert wrote: > > > > > > > > > > > > > > > > > I

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-19 Thread Rodrigo Vivi
On Tue, Jul 17, 2018 at 06:05:51PM -0700, Nathan Ciobanu wrote: > On Tue, Jul 17, 2018 at 03:21:17PM -0700, Dhinakaran Pandiyan wrote: > > On Mon, 2018-07-16 at 16:51 -0700, Marc Herbert wrote: > > > > > > > > > > > > > > I think the bug is with this infinite loop which is at the mercy > > > > >

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-17 Thread Dhinakaran Pandiyan
On Tue, 2018-07-17 at 18:05 -0700, Nathan Ciobanu wrote: > On Tue, Jul 17, 2018 at 03:21:17PM -0700, Dhinakaran Pandiyan wrote: > > > > On Mon, 2018-07-16 at 16:51 -0700, Marc Herbert wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > I think the bug is with this infinite loop which i

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-17 Thread Nathan Ciobanu
On Tue, Jul 17, 2018 at 03:21:17PM -0700, Dhinakaran Pandiyan wrote: > On Mon, 2018-07-16 at 16:51 -0700, Marc Herbert wrote: > > > > > > > > > > > I think the bug is with this infinite loop which is at the mercy > > > > of an external device > > > > and in my case I have this MST hub which appea

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-17 Thread Dhinakaran Pandiyan
On Mon, 2018-07-16 at 16:51 -0700, Marc Herbert wrote: > > > > > > > > I think the bug is with this infinite loop which is at the mercy > > > of an external device > > > and in my case I have this MST hub which appears to be DP 1.2 > > > that triggers the > > > infinite loop case. We have to limi

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Marc Herbert
>> I think the bug is with this infinite loop which is at the mercy of an >> external device >> and in my case I have this MST hub which appears to be DP 1.2 that triggers >> the >> infinite loop case. We have to limit the number of iterations and >> DP 1.4 spec happened to fix this issue. I'm a

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Rodrigo Vivi
On Mon, Jul 16, 2018 at 04:23:23PM -0700, Nathan Ciobanu wrote: > On Mon, Jul 16, 2018 at 03:34:58PM -0700, Rodrigo Vivi wrote: > > On Mon, Jul 16, 2018 at 11:14:45AM -0700, Nathan Ciobanu wrote: > > > Limit the link training clock recovery loop to 10 failed attempts at > > > LANEx_CR_DONE per DP 1

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Rodrigo Vivi
On Mon, Jul 16, 2018 at 04:27:47PM -0700, Nathan Ciobanu wrote: > On Mon, Jul 16, 2018 at 03:30:49PM -0700, Rodrigo Vivi wrote: > > On Mon, Jul 16, 2018 at 12:22:13PM -0700, Marc Herbert wrote: > > > > > > While the shortness of v3 is really nice, I think it's rather a good > > > opportunity to ma

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Nathan Ciobanu
On Mon, Jul 16, 2018 at 03:30:49PM -0700, Rodrigo Vivi wrote: > On Mon, Jul 16, 2018 at 12:22:13PM -0700, Marc Herbert wrote: > > > > While the shortness of v3 is really nice, I think it's rather a good > > opportunity to make much clearer (as a separate, no functional change > > patch?) its exis

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Nathan Ciobanu
On Mon, Jul 16, 2018 at 03:34:58PM -0700, Rodrigo Vivi wrote: > On Mon, Jul 16, 2018 at 11:14:45AM -0700, Nathan Ciobanu wrote: > > Limit the link training clock recovery loop to 10 failed attempts at > > LANEx_CR_DONE per DP 1.4 spec section 3.5.1.2.2. > > Thanks... so this made me look to DP 1.3

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Rodrigo Vivi
On Mon, Jul 16, 2018 at 11:14:45AM -0700, Nathan Ciobanu wrote: > Limit the link training clock recovery loop to 10 failed attempts at > LANEx_CR_DONE per DP 1.4 spec section 3.5.1.2.2. Thanks... so this made me look to DP 1.3 and DP 1.4 differences here. Are we already addressing all new conditio

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Rodrigo Vivi
On Mon, Jul 16, 2018 at 12:22:13PM -0700, Marc Herbert wrote: > > While the shortness of v3 is really nice, I think it's rather a good > opportunity to make much clearer (as a separate, no functional change > patch?) its existing terminating condition(s) and what the existing loop > iterates on.

Re: [Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Marc Herbert
While the shortness of v3 is really nice, I think it's rather a good opportunity to make much clearer (as a separate, no functional change patch?) its existing terminating condition(s) and what the existing loop iterates on. I mean it's painful and risky enough to _combine multiple counters in th

[Intel-gfx] [PATCH v3] drm/i915/dp: Give up link training clock recovery after 10 failed attempts

2018-07-16 Thread Nathan Ciobanu
Limit the link training clock recovery loop to 10 failed attempts at LANEx_CR_DONE per DP 1.4 spec section 3.5.1.2.2. Some USB-C MST hubs cause us to get stuck in this loop indefinitely requesting voltage swing: 0, pre-emphasis level: 2 voltage swing: 1, pre-emphasis level: 2 voltage s