Re: [PATCH] drm/i915: Don't WARN on BDW when PCH is propperly identified.

From: Jani Nikula <jani.nikula@linux.intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: Re: [PATCH] drm/i915: Don't WARN on BDW when PCH is	propperly identified.
Date: Tue, 20 Jan 2015 10:51:52 +0200	[thread overview]
Message-ID: <87ppa9dec7.fsf@intel.com> (raw)
In-Reply-To: <1421698435-13617-1-git-send-email-rodrigo.vivi@intel.com>

On Mon, 19 Jan 2015, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
> We have BDW that PCH might not be propperly identified and we force it
> to be LPT.  However when we correctly identify it is LPT we
> incorrectly WARN that this isn't a Haswell. For now we have many
> platforms out there we still need to force LPT so let's keep the force
> below, but let's remove the WARN when everything is propperly
> identified.

Before this we haven't tested the BDW + non-LP LPT combination. Maybe we
should do some review of any checks against
INTEL_PCH_LPT_LP_DEVICE_ID_TYPE in BDW code. Those have always matched
before.

If the pch ids are getting identified right, shouldn't we then move
INTEL_PCH_LPT_LP_DEVICE_ID_TYPE check higher up in the pch
identification, and accept BDW for that too, and make IS_BROADWELL(dev)
a fallback after both the LPT variants have been checked?

Finally the condition below is busted!

> For reference we started receiving logs with this uncessary and incorrect WARN.
>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Reference: https://bugs.freedesktop.org/attachment.cgi?id=110972
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 308774f..d4ed3a9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -462,7 +462,7 @@ void intel_detect_pch(struct drm_device *dev)
>  			} else if (id == INTEL_PCH_LPT_DEVICE_ID_TYPE) {
>  				dev_priv->pch_type = PCH_LPT;
>  				DRM_DEBUG_KMS("Found LynxPoint PCH\n");
> -				WARN_ON(!IS_HASWELL(dev));
> +				WARN_ON(!IS_HASWELL(dev) || !IS_BROADWELL(dev));

This will warn always...

BR,
Jani.

>  				WARN_ON(IS_HSW_ULT(dev));
>  			} else if (IS_BROADWELL(dev)) {
>  				dev_priv->pch_type = PCH_LPT;
> -- 
> 2.1.0
>
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-- 
Jani Nikula, Intel Open Source Technology Center
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