linux-kernel - Re: [PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to 1000us

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Date:	Tue, 29 Mar 2016 10:05:40 -0400
From:	Lyude Paul <cpaul@...hat.com>
To:	Daniel Vetter <daniel@...ll.ch>
Cc:	intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
	arthur.j.runyan@...el.com, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to
 1000us

Yep, the rest of the patchset works fine without this patch

On Tue, 2016-03-29 at 10:27 +0200, Daniel Vetter wrote:
> 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 <cpaul@...hat.com>
> > ---
> >  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 <daniel.vetter@...ll.ch>
> 
> > 
> >  
> >  /**
> >   * DOC: dp helpers
> > -- 
> > 2.5.5
> > 
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
-- 
Cheers,
	Lyude

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