From: Jesse Barnes <jbarnes@virtuousgeek.org>
To: ville.syrjala@linux.intel.com
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Use wait_for() to wait for Punit to change GPU freq on VLV
Date: Wed, 26 Jun 2013 09:26:25 -0700 [thread overview]
Message-ID: <20130626092625.60a08794@jbarnes-desktop> (raw)
In-Reply-To: <1372257804-13715-1-git-send-email-ville.syrjala@linux.intel.com>
On Wed, 26 Jun 2013 17:43:24 +0300
ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Use wait_for() instead of the open coded loop to avoid spreading the
> same old timeout related bugs.
>
> This changes the loop to use msleep(1) instead of udelay(10) when the
> Punit had not yet completed the frequency change. In practice that
> doesn't seem to hurt performance as the Punit appears to be ready pretty
> much always.
>
> Also give the status bit a name, instead of using the magic number 1.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 1 +
> drivers/gpu/drm/i915/intel_pm.c | 11 ++---------
> 2 files changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 10ac3d5..d5199a3 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -363,6 +363,7 @@
> #define PUNIT_REG_GPU_LFM 0xd3
> #define PUNIT_REG_GPU_FREQ_REQ 0xd4
> #define PUNIT_REG_GPU_FREQ_STS 0xd8
> +#define GENFREQSTATUS (1<<0)
> #define PUNIT_REG_MEDIA_TURBO_FREQ_REQ 0xdc
>
> #define PUNIT_FUSE_BUS2 0xf6 /* bits 47:40 */
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index aa48fc6..bff5709 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3074,19 +3074,12 @@ void gen6_set_rps(struct drm_device *dev, u8 val)
> */
> static void vlv_update_rps_cur_delay(struct drm_i915_private *dev_priv)
> {
> - unsigned long timeout = jiffies + msecs_to_jiffies(10);
> u32 pval;
>
> WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
>
> - do {
> - pval = vlv_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS);
> - if (time_after(jiffies, timeout)) {
> - DRM_DEBUG_DRIVER("timed out waiting for Punit\n");
> - break;
> - }
> - udelay(10);
> - } while (pval & 1);
> + if (wait_for(((pval = vlv_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS)) & GENFREQSTATUS) == 0, 10))
> + DRM_DEBUG_DRIVER("timed out waiting for Punit\n");
>
> pval >>= 8;
>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
--
Jesse Barnes, Intel Open Source Technology Center
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next prev parent reply other threads:[~2013-06-26 16:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-25 16:21 [PATCH 0/6] drm/i915: VLV rps stuff ville.syrjala
2013-06-25 16:21 ` [PATCH 1/6] drm/i915: Clean up VLV rps code a bit ville.syrjala
2013-06-25 18:59 ` Jesse Barnes
2013-06-25 16:21 ` [PATCH 2/6] drm/i915: Don't wait for Punit after each freq change on VLV ville.syrjala
2013-06-25 19:02 ` Jesse Barnes
2013-06-25 16:21 ` [PATCH 3/6] drm/i915: Optimize the VLV Punit wait a bit ville.syrjala
2013-06-25 19:03 ` Jesse Barnes
2013-06-26 10:17 ` Daniel Vetter
2013-06-26 14:43 ` [PATCH] drm/i915: Use wait_for() to wait for Punit to change GPU freq on VLV ville.syrjala
2013-06-26 16:26 ` Jesse Barnes [this message]
2013-07-02 13:41 ` Daniel Vetter
2013-07-02 14:01 ` Daniel Vetter
2013-06-25 16:21 ` [PATCH 4/6] drm/i915: Use msecs_to_jiffies_timeout when waiting for Punit freq change ville.syrjala
2013-06-25 19:03 ` Jesse Barnes
2013-06-25 16:21 ` [PATCH 5/6] drm/i915: Make the rps new_delay comparison more readable ville.syrjala
2013-06-25 19:06 ` Jesse Barnes
2013-06-25 16:21 ` [PATCH 6/6] drm/i915: GEN6_RP_INTERRUPT_LIMITS doesn't seem to exist on VLV ville.syrjala
2013-06-25 19:06 ` Jesse Barnes
2013-06-26 10:19 ` Daniel Vetter
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