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

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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

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[PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to 1000us Lyude <cpaul@redhat.com> - 2016-03-28 16:40 +0200
  Re: [PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to  1000us Daniel Vetter <daniel@ffwll.ch> - 2016-03-29 10:30 +0200
    Re: [PATCH v4 RESEND 1/5] drm/dp_helper: Increase retry interval to  1000us Lyude Paul <cpaul@redhat.com> - 2016-03-29 16:10 +0200

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