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From: Daniel Vetter <daniel@ffwll.ch>
To: Lyude <cpaul@redhat.com>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	arthur.j.runyan@intel.com,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to 1000us
Date: Tue, 29 Mar 2016 10:27:33 +0200	[thread overview]
Message-ID: <20160329082732.GL2510@phenom.ffwll.local> (raw)
In-Reply-To: <1459175606-13875-2-git-send-email-cpaul@redhat.com>

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@redhat.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@ffwll.ch>

>  
>  /**
>   * 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

  reply	other threads:[~2016-03-29  8:27 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-28 14:33 [PATCH v4 RESEND 0/5] Move workarounds from intel_dp_dpcd_read_wake() into drm's DP helpers Lyude
2016-03-28 14:33 ` [PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to 1000us Lyude
2016-03-29  8:27   ` Daniel Vetter [this message]
2016-03-29 14:05     ` Lyude Paul
2016-03-28 14:33 ` [PATCH v4 RESEND 2/5] drm/dp_helper: Always wait before retrying native aux transactions Lyude
2016-03-28 14:33 ` [PATCH v4 RESEND 3/5] drm/dp_helper: Retry aux transactions on all errors Lyude
2016-03-28 14:33 ` [PATCH v4 RESEND 4/5] drm/dp_helper: Perform throw-away read before actual read in drm_dp_dpcd_read() Lyude
2016-03-29 20:43   ` [PATCH v5 " Lyude
2016-03-28 14:33 ` [PATCH v4 RESEND 5/5] drm/i915: Get rid of intel_dp_dpcd_read_wake() Lyude
2016-03-30 14:26   ` Jani Nikula
2016-04-12 10:17 ` [PATCH v4 RESEND 0/5] Move workarounds from intel_dp_dpcd_read_wake() into drm's DP helpers Jani Nikula
2016-04-12 15:59   ` Lyude
2016-04-13 14:58   ` [PATCH v5 0/4] " Lyude
2016-04-13 14:58     ` [PATCH v5 1/4] drm/dp_helper: Always wait before retrying native aux transactions Lyude
2016-04-13 14:58     ` [PATCH v5 2/4] drm/dp_helper: Retry aux transactions on all errors Lyude
2016-04-13 14:58     ` [PATCH v5 3/4] drm/dp_helper: Perform throw-away read before actual read in drm_dp_dpcd_read() Lyude
2016-04-14 17:01       ` Ville Syrjälä
2016-04-15 14:25         ` [PATCH v6 " Lyude
2016-04-15 14:31           ` Ville Syrjälä
2016-04-13 14:58     ` [PATCH v5 4/4] drm/i915: Get rid of intel_dp_dpcd_read_wake() Lyude
2016-04-22 16:54       ` Daniel Vetter

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