From: Chris Wilson <chris@chris-wilson.co.uk>
To: Ben Widawsky <ben@bwidawsk.net>, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 2/4] drm/i915: fix rc6 initialization on Ironlake
Date: Sat, 19 Mar 2011 07:55:01 +0000 [thread overview]
Message-ID: <0d30dc$lgdgge@orsmga001.jf.intel.com> (raw)
In-Reply-To: <1300489968-8574-3-git-send-email-ben@bwidawsk.net>
On Fri, 18 Mar 2011 16:12:46 -0700, Ben Widawsky <ben@bwidawsk.net> wrote:
> There is a race condition between setting PWRCTXA and executing
> MI_SET_CONTEXT. PWRCTXA must not be set until a valid context has been
> written (or else the GPU could possible go into rc6, and return to an
> invalid context).
>
> Reported-and-Tested-by: Gu Rui <chaos.proton@gmail.com>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=28582
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> ---
> drivers/gpu/drm/i915/intel_display.c | 32 +++++++++++++++++++++++++++++---
> 1 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 790af25..c1e9c30 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6603,14 +6603,27 @@ static int ironlake_setup_rc6(struct drm_device *dev)
> return 0;
> }
>
> +static int ironlake_wait_set_context(struct drm_device *dev)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + struct intel_ring_buffer *ring = LP_RING(dev_priv);
> + int ret = -EAGAIN;
> +
> + ret = wait_for((I915_READ_HEAD(ring) == I915_READ_TAIL(ring)), 1000);
> + if (ret && atomic_read(&dev_priv->mm.wedged)) {
> + ret = -EIO;
> + } else if (!ret) { /* head == tail */
> + ret = 0;
> + }
> +
> + return ret;
> +}
Let's make this a more generic function because it does look useful.
static inline int intel_ring_wait_idle(struct intel_ring_buffer *ring)
{
return intel_wait_ring_buffer(ring, ring->space - 8);
}
> +
> void ironlake_enable_rc6(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> int ret;
>
> - /* rc6 disabled by default due to repeated reports of hanging during
> - * boot and resume.
> - */
> if (!i915_enable_rc6)
> return;
>
> @@ -6640,6 +6653,19 @@ void ironlake_enable_rc6(struct drm_device *dev)
> OUT_RING(MI_FLUSH);
> ADVANCE_LP_RING();
>
> + /*
> + * Wait for the command parser to advance past MI_SET_CONTEXT. The HW
> + * does an implicit flush, combined with MI_FLUSH above, it should be
> + * safe to assume that renderctx is valid
> + */
> + ret = ironlake_wait_set_context(dev);
> + if (ret) {
> + if (ret == -EAGAIN)
> + DRM_ERROR("rc6 switch took too long, freeing the bo");
Just report the failure in all cases and avoid jargon (if possible)!
if (intel_ring_wait_idle(LP_RING(dev_priv))) {
DRM_ERROR("failed to enable automatic power saving\n");
return;
}
--
Chris Wilson, Intel Open Source Technology Centre
next prev parent reply other threads:[~2011-03-19 7:55 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-18 23:12 [PATCH 0/4] Re-enable RC6 on Ironlake Ben Widawsky
2011-03-18 23:12 ` [PATCH 1/4] drm/i915: fix ilk rc6 teardown locking Ben Widawsky
2011-03-19 7:44 ` Chris Wilson
2011-03-19 18:38 ` [PATCH v2 " Ben Widawsky
2011-03-19 18:46 ` [PATCH " Keith Packard
2011-03-20 1:14 ` [PATCH v2 1/5] " Ben Widawsky
2011-03-20 1:14 ` [PATCH v2 2/5] drm/1915: ringbuffer wait for idle function Ben Widawsky
2011-03-20 1:14 ` [PATCH v2 3/5] drm/i915: fix rc6 initialization on Ironlake Ben Widawsky
2011-03-20 1:14 ` [PATCH v2 4/5] drm/i915: debugfs for context information Ben Widawsky
2011-03-20 1:14 ` [PATCH v2 5/5] drm/i915: re-enable rc6 for ironlake Ben Widawsky
2011-03-18 23:12 ` [PATCH 2/4] drm/i915: fix rc6 initialization on Ironlake Ben Widawsky
2011-03-19 7:55 ` Chris Wilson [this message]
2011-03-20 0:07 ` Ben Widawsky
2011-03-18 23:12 ` [PATCH 3/4] drm/i915: debugfs for context information Ben Widawsky
2011-03-18 23:12 ` [PATCH 4/4] drm/i915: re-enable rc6 for ironlake Ben Widawsky
2011-04-27 7:49 ` Chris Wilson
2011-04-27 21:20 ` Jesse Barnes
2011-04-27 22:03 ` Chris Wilson
2011-04-27 22:49 ` Jesse Barnes
2011-04-28 17:10 ` Ben Widawsky
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