Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755423AbcC2I1f (ORCPT ); Tue, 29 Mar 2016 04:27:35 -0400 Received: from mail-wm0-f44.google.com ([74.125.82.44]:36985 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752206AbcC2I1a (ORCPT ); Tue, 29 Mar 2016 04:27:30 -0400 Date: Tue, 29 Mar 2016 10:27:33 +0200 From: Daniel Vetter To: Lyude Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, arthur.j.runyan@intel.com, open list Subject: Re: [PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to 1000us Message-ID: <20160329082732.GL2510@phenom.ffwll.local> Mail-Followup-To: Lyude , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, arthur.j.runyan@intel.com, open list References: <1459175606-13875-1-git-send-email-cpaul@redhat.com> <1459175606-13875-2-git-send-email-cpaul@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1459175606-13875-2-git-send-email-cpaul@redhat.com> X-Operating-System: Linux phenom 4.4.0-1-amd64 User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1487 Lines: 44 On Mon, Mar 28, 2016 at 10:33:22AM -0400, Lyude wrote: > This is part of a patch series to migrate all of the workarounds for > commonly seen behavior from bad sinks in intel_dp_dpcd_read_wake() to > drm's DP helper. > > Signed-off-by: Lyude > --- > drivers/gpu/drm/drm_dp_helper.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index 7d58f59..d1128fb 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -160,7 +160,7 @@ int drm_dp_bw_code_to_link_rate(u8 link_bw) > } > EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate); > > -#define AUX_RETRY_INTERVAL 500 /* us */ > +#define AUX_RETRY_INTERVAL 1000 /* us */ Was this to adapt to the msleep(1) in the i915 function? If so it's kinda wrong anyway, since an msleep(1) actually sleeps 1 jiffy, and on most systems that's a lot more than 1 ms. If it all still works, I'd just drop this patch here. I suspect that the magic is all in the more aggressive retrying and the throwaway read, not in how long we actually wait. On patches 2-5: Reviewed-by: Daniel Vetter > > /** > * DOC: dp helpers > -- > 2.5.5 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch