From: "Wentland, Harry" <Harry.Wentland-5C7GfCeVMHo@public.gmane.org>
To: "sylvain.bertrand-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org"
<sylvain.bertrand-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: "Barberiz, John" <John.Barberiz-5C7GfCeVMHo@public.gmane.org>,
"Lakha,
Bhawanpreet" <Bhawanpreet.Lakha-5C7GfCeVMHo@public.gmane.org>,
"amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org"
<amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>
Subject: Re: [PATCH 01/35] drm/amd/display: Use udelay when waiting between aux retries
Date: Mon, 4 Feb 2019 15:43:36 +0000 [thread overview]
Message-ID: <e7211c67-8ea3-e8f5-8f91-d7af94c1a603@amd.com> (raw)
In-Reply-To: <20190201225559.GA1064@freedom>
On 2019-02-01 5:55 p.m., sylvain.bertrand@gmail.com wrote:
> On Fri, Feb 01, 2019 at 09:20:56PM +0000, Wentland, Harry wrote:
>> DRM's AUX code uses usleep_range in drm_dp_dpcd_access.
>
> My bad, forgot about the usleep_range switch. That said AUX_RETRY_INTERVAL is
> 500 us, with a usleep_range top bound of 600 us.
>
> Then, it would mean DC DP timeout retries would happen after ~1ms, and drm
> ~600us. Additionaly, it seems that the number of retries are 3 in drm code and
> 7 in DC code.
>
DRM actually bumped this to 32 due to an issue with a Dell 4k display.
> I may be wrong, but it seems DC code is much more "insisting" on auxchannel
> (edid retrieval) and much more forgiving on monitor ability to timeout in
> time (~1ms).
>
> If I did read the code the right way, it may be more reasonable to have similar
> behavior in drm code than in DC code, right?
>
It depends. I wouldn't call one or the other more correct. I seem to remember that the DP spec is quite vague on these retries but I could be mistaken. Since our driver hasn't show any problems with the DRM code and I believe others (such as i915) also pass DP compliance without issues I wouldn't proactively change this.
Harry
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next prev parent reply other threads:[~2019-02-04 15:43 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-01 15:28 [PATCH 00/35] DC Changes Jan 31, 2019 Bhawanpreet Lakha
[not found] ` <20190201152847.11151-1-Bhawanpreet.Lakha-5C7GfCeVMHo@public.gmane.org>
2019-02-01 15:28 ` [PATCH 01/35] drm/amd/display: Use udelay when waiting between aux retries Bhawanpreet Lakha
[not found] ` <20190201152847.11151-2-Bhawanpreet.Lakha-5C7GfCeVMHo@public.gmane.org>
2019-02-01 17:31 ` sylvain.bertrand-Re5JQEeQqe8AvxtiuMwx3w
2019-02-01 19:16 ` Wentland, Harry
[not found] ` <fda8f6ec-5a75-6456-3034-f3714b304b77-5C7GfCeVMHo@public.gmane.org>
2019-02-01 20:08 ` sylvain.bertrand-Re5JQEeQqe8AvxtiuMwx3w
2019-02-01 20:47 ` sylvain.bertrand-Re5JQEeQqe8AvxtiuMwx3w
2019-02-01 21:20 ` Wentland, Harry
[not found] ` <058665e8-0241-8fc1-8a2a-9f1d7484b29e-5C7GfCeVMHo@public.gmane.org>
2019-02-01 22:55 ` sylvain.bertrand-Re5JQEeQqe8AvxtiuMwx3w
2019-02-04 15:43 ` Wentland, Harry [this message]
[not found] ` <e7211c67-8ea3-e8f5-8f91-d7af94c1a603-5C7GfCeVMHo@public.gmane.org>
2019-02-04 16:21 ` sylvain.bertrand-Re5JQEeQqe8AvxtiuMwx3w
2019-02-01 15:28 ` [PATCH 02/35] drm/amd/display: Apply all surface updates onto surfaces Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 03/35] drm/amd/display: Use the right surface for flip and FreeSync Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 04/35] drm/amd/display: Reformat dm_determine_update_type_for_commit Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 05/35] drm/amd/display: Initialize stream_update to zero Bhawanpreet Lakha
[not found] ` <20190201152847.11151-6-Bhawanpreet.Lakha-5C7GfCeVMHo@public.gmane.org>
2019-02-03 17:45 ` Nils Wallménius
2019-02-01 15:28 ` [PATCH 06/35] drm/amd/display: Remove FreeSync timing changed debug output Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 07/35] drm/amd/display: Add monitor patch for backlight Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 08/35] drm/amd/display: fix issue with DC brightness low with VB Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 09/35] drm/amd/display: dmcu is blocking due to wrong disable ABM command Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 10/35] drm/amd/display: Check that vrefresh is in freesync range Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 11/35] drm/amd/display: DGAM enabled for HDR Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 12/35] drm/amd/display: determine if a pipe is synced by plane state Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 13/35] drm/amd/display: 3.2.16 Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 14/35] drm/amd/display: add gpio lock/unlock Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 15/35] drm/amd/display: make vline_config parameter const Bhawanpreet Lakha
[not found] ` <20190201152847.11151-16-Bhawanpreet.Lakha-5C7GfCeVMHo@public.gmane.org>
2019-02-03 17:49 ` Nils Wallménius
[not found] ` <CA+nq7DtCqojJynhoxwyPnUGXf4gPzkrypi7dUT_ahQ9DDygqKQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-02-04 15:45 ` [PATCH 15/35] drm/amd/display: pass vline_config parameter by reference Bhawanpreet Lakha
[not found] ` <20190204154522.22215-15-Bhawanpreet.Lakha-5C7GfCeVMHo@public.gmane.org>
2019-02-04 15:49 ` Fw: " Lakha, Bhawanpreet
2019-02-01 15:28 ` [PATCH 16/35] drm/amd/display: Modify ABM 2.2 Max Reduction Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 17/35] drm/amd/display: store timing sync info in dc_stream_status Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 18/35] drm/amd/display: add a debug flag to force odm combine Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 19/35] drm/amd/display: Apply fake sink back to MST sequence Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 20/35] drm/amd/display: Disconnect mpcc when changing tg Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 21/35] drm/amd/display: Don't re-program planes for DPMS changes Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 22/35] drm/amd/display: Clear dc_sink after it gets released Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 23/35] drm/amd/display: Calc vline position in dc Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 24/35] drm/amd/display: Disable Stutter for Stereo 3D Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 25/35] drm/amd/display: DC VM Fixes Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 26/35] drm/amd/display: link_rate_set should index into table Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 27/35] drm/amd/display: PIP overlay corruption Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 28/35] drm/amd/display:3.2.17 Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 29/35] drm/amd/display: interface to check if timing can be seamless Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 30/35] drm/amd/display: refactor out programming of vupdate interrupt Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 31/35] drm/amd/display: add way to determine if link is active Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 32/35] drm/amd/display: add seamless boot flag to stream Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 33/35] drm/amd/display: refactor programming of DRR Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 34/35] drm/amd/display: refactor init_hw to isolate pipe related init Bhawanpreet Lakha
2019-02-01 15:28 ` [PATCH 35/35] drm/amd/display: add n_vid_mul and half pix_rate for odm Bhawanpreet Lakha
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