[Intel-gfx] [PATCH] drm/i915: disable hotplug detect before Ironlake CRT detect

[Peter Clifton]

Is HPD a common acronym? Perhaps we could spell it out fully so the
comments are clearer to those less familiar with the hardware?


On Mon, 2010-01-25 at 10:35 +0800, Zhenyu Wang wrote:
> On 2009.12.08 23:33:23 -0800, Eric Anholt wrote:
> > This seems like yet another instance of "we need to turn off hotplug
> > detection during the detection process" -- can we just do that already?
> 
> Sorry for ignore this one... Here's current refreshed patch.
> 
> thanks.
> 
> From f18aaedb814e3c797bcbbbb885f74ff701dd9d85 Mon Sep 17 00:00:00 2001
> From: Zhenyu Wang <zhenyuw at linux.intel.com>
> Date: Mon, 25 Jan 2010 10:23:10 +0800
> Subject: [PATCH] drm/i915: disable hotplug detect before Ironlake CRT detect
> 
> This trys to fix CRT detect loop hang seen on some Ironlake form
> factor, to clear up hotplug detect state before taking CRT detect
> to make sure next HPD cycle is consistent.
> 
> Cc: Stable Team <stable at kernel.org>
> Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_crt.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
> index ddefc87..79dd402 100644
> --- a/drivers/gpu/drm/i915/intel_crt.c
> +++ b/drivers/gpu/drm/i915/intel_crt.c
> @@ -157,6 +157,9 @@ static bool intel_ironlake_crt_detect_hotplug(struct drm_connector *connector)
>  	adpa = I915_READ(PCH_ADPA);
>  
>  	adpa &= ~ADPA_CRT_HOTPLUG_MASK;
> +	/* disable HPD first */

                     ^^^____ Doesn't cost much extra to expand this 
                             acronym so those less familiar with the
                             code / hardware can understand this.

> +	I915_WRITE(PCH_ADPA, adpa);
> +	(void)I915_READ(PCH_ADPA);
>  
>  	adpa |= (ADPA_CRT_HOTPLUG_PERIOD_128 |
>  			ADPA_CRT_HOTPLUG_WARMUP_10MS |
> -- 
> 1.6.6
> 
> 
> 
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