Re: [PATCH] drm/i915: unify PM interrupt preinstall sequence

From: Paulo Zanoni <przanoni@gmail.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH] drm/i915: unify PM interrupt preinstall sequence
Date: Wed, 10 Jul 2013 17:05:07 -0300	[thread overview]
Message-ID: <CA+gsUGRBxwvfU_RNxGreFcHDf7o8X+X4WQGm77cnm3b34dJG2Q@mail.gmail.com> (raw)
In-Reply-To: <1373403610-1754-1-git-send-email-daniel.vetter@ffwll.ch>

2013/7/9 Daniel Vetter <daniel.vetter@ffwll.ch>:
> Since the addition of VECS we have a slightly different enable
> sequence for PM interrupts on ivb/hsw vs snb and vlv. Usually that
> will end up in hard to track down surprises.
>
> Hence unifiy things and since we have copies of this code in 3 places
> now, extract it into its own little helper.
>
> v3: Rebase on top of the retained double-GTIIR clearing. Also
> resurrect the masking/disabling of the gen6+ PM interrupts as spotted
> by Ben Widaswky.
>
> v4: Move the DE interrupt reset code out of gen5_gt_irq_preinstall
> back to ironlake_irq_preinstall where it really belongs. Spotted by
> Paulo.
>
> Cc: Paulo Zanoni <przanoni@gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 39 +++++++++++++++++++++------------------
>  1 file changed, 21 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index cf1a21a..d5c3bef 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2583,6 +2583,23 @@ static void ibx_irq_preinstall(struct drm_device *dev)
>         POSTING_READ(SDEIER);
>  }
>
> +static void gen5_gt_irq_preinstall(struct drm_device *dev)
> +{
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +       /* and GT */
> +       I915_WRITE(GTIMR, 0xffffffff);
> +       I915_WRITE(GTIER, 0x0);
> +       POSTING_READ(GTIER);
> +
> +       if (INTEL_INFO(dev)->gen >= 6) {
> +               /* and GT */

This comment should be /* Power management */, but it's completely
useless, so you could kill it and also the /* and GT */ above.

> +               I915_WRITE(GEN6_PMIMR, 0xffffffff);
> +               I915_WRITE(GEN6_PMIER, 0x0);
> +               POSTING_READ(GEN6_PMIER);
> +       }
> +}
> +
>  /* drm_dma.h hooks
>  */
>  static void ironlake_irq_preinstall(struct drm_device *dev)
> @@ -2593,16 +2610,11 @@ static void ironlake_irq_preinstall(struct drm_device *dev)
>
>         I915_WRITE(HWSTAM, 0xeffe);
>
> -       /* XXX hotplug from PCH */
> -
>         I915_WRITE(DEIMR, 0xffffffff);
>         I915_WRITE(DEIER, 0x0);
>         POSTING_READ(DEIER);
>
> -       /* and GT */
> -       I915_WRITE(GTIMR, 0xffffffff);
> -       I915_WRITE(GTIER, 0x0);
> -       POSTING_READ(GTIER);
> +       gen5_gt_irq_preinstall(dev);

With this, we're now initializing GEN6_PM* on SandyBridge since it
uses ironlake_irq_preinstall. That sounds like a good thing. We could
either mention this in the commit message or do it in a separate
patch.

>
>         ibx_irq_preinstall(dev);
>  }
> @@ -2621,15 +2633,7 @@ static void ivybridge_irq_preinstall(struct drm_device *dev)
>         I915_WRITE(DEIER, 0x0);
>         POSTING_READ(DEIER);
>
> -       /* and GT */
> -       I915_WRITE(GTIMR, 0xffffffff);
> -       I915_WRITE(GTIER, 0x0);
> -       POSTING_READ(GTIER);
> -
> -       /* Power management */
> -       I915_WRITE(GEN6_PMIMR, 0xffffffff);
> -       I915_WRITE(GEN6_PMIER, 0x0);
> -       POSTING_READ(GEN6_PMIER);
> +       gen5_gt_irq_preinstall(dev);
>
>         ibx_irq_preinstall(dev);
>  }
> @@ -2650,9 +2654,8 @@ static void valleyview_irq_preinstall(struct drm_device *dev)
>         /* and GT */
>         I915_WRITE(GTIIR, I915_READ(GTIIR));
>         I915_WRITE(GTIIR, I915_READ(GTIIR));
> -       I915_WRITE(GTIMR, 0xffffffff);
> -       I915_WRITE(GTIER, 0x0);
> -       POSTING_READ(GTIER);
> +
> +       gen5_gt_irq_preinstall(dev);

Valleyview is Gen 7, right? So now we're also initializing GEN6_PMI*
on it. So same comments from SNB apply here. Maybe you should change
the commit title to "Initialize the PM interrupts on SNB and VLV".

>
>         I915_WRITE(DPINVGTT, 0xff);
>
> --
> 1.8.1.4
>

-- 
Paulo Zanoni