From mboxrd@z Thu Jan 1 00:00:00 1970 From: "S, Deepak" Subject: Re: [PATCH v4 2/2] drm/i915/vlv: WA to fix Voltage not getting dropped to Vmin when Gfx is power gated. Date: Tue, 28 Jan 2014 20:02:56 +0530 Message-ID: <52E7BF98.90404@intel.com> References: <1390838706-10934-1-git-send-email-deepak.s@intel.com> <1390838706-10934-3-git-send-email-deepak.s@intel.com> <20140127165227.GH9772@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id 4F53D11D6E3 for ; Tue, 28 Jan 2014 06:33:00 -0800 (PST) In-Reply-To: <20140127165227.GH9772@phenom.ffwll.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org To: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On 1/27/2014 10:22 PM, Daniel Vetter wrote: > On Mon, Jan 27, 2014 at 09:35:06PM +0530, deepak.s@intel.com wrote: >> From: Deepak S >> >> When we enter RC6 and GFX Clocks are off, the voltage remains higher >> than Vmin. When we try to set the freq to RPn, it might fail since the >> Gfx clocks are down. So to fix this in Gfx idle, Bring the GFX clock up >> and set the freq to RPn then move GFx down. >> >> v2: remove vlv_update_rps_cur_delay function. Update commit message (Daniel) >> >> v3: Fix the timeout during wait for gfx clock (Jesse) >> >> v4: addressed comments on set freq and punit wait (Ville) >> >> Signed-off-by: Deepak S >> --- >> drivers/gpu/drm/i915/i915_reg.h | 4 ++++ >> drivers/gpu/drm/i915/intel_pm.c | 53 ++++++++++++++++++++++++++++++++++++++++- >> 2 files changed, 56 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h >> index 242f540..feaa83b 100644 >> --- a/drivers/gpu/drm/i915/i915_reg.h >> +++ b/drivers/gpu/drm/i915/i915_reg.h >> @@ -4944,6 +4944,10 @@ >> GEN6_PM_RP_DOWN_THRESHOLD | \ >> GEN6_PM_RP_DOWN_TIMEOUT) >> >> +#define VLV_GTLC_SURVIVABILITY_REG 0x130098 >> +#define VLV_GFX_CLK_STATUS_BIT (1<<3) >> +#define VLV_GFX_CLK_FORCE_ON_BIT (1<<2) >> + >> #define GEN6_GT_GFX_RC6_LOCKED 0x138104 >> #define VLV_COUNTER_CONTROL 0x138104 >> #define VLV_COUNT_RANGE_HIGH (1<<15) >> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c >> index c6a07c9..84e20d0 100644 >> --- a/drivers/gpu/drm/i915/intel_pm.c >> +++ b/drivers/gpu/drm/i915/intel_pm.c >> @@ -3035,6 +3035,56 @@ void gen6_set_rps(struct drm_device *dev, u8 val) >> trace_intel_gpu_freq_change(val * 50); >> } >> >> +/* vlv_set_rps_idle: Set the frequency to Rpn if Gfx clocks are down >> + * >> + * * If Gfx is Idle, then >> + * 1. Mask Turbo interrupts >> + * 2. Bring up Gfx clock >> + * 3. Change the freq to Rpn and wait till P-Unit updates freq >> + * 4. Clear the Force GFX CLK ON bit so that Gfx can down >> + * 5. Unmask Turbo interrupts >> +*/ >> +static void vlv_set_rps_idle(struct drm_i915_private *dev_priv) >> +{ >> + /* >> + * When we are idle. Drop to min voltage state. >> + */ >> + >> + if (dev_priv->rps.cur_delay <= dev_priv->rps.min_delay) >> + return; >> + >> + /* Mask turbo interrupt so that they will not come in between */ >> + I915_WRITE(GEN6_PMINTRMSK, 0xffffffff); >> + >> + /* Bring up the Gfx clock */ >> + I915_WRITE(VLV_GTLC_SURVIVABILITY_REG, >> + I915_READ(VLV_GTLC_SURVIVABILITY_REG) | >> + VLV_GFX_CLK_FORCE_ON_BIT); >> + >> + if (wait_for_atomic(((VLV_GFX_CLK_STATUS_BIT & > > Do we really need an atomic register busy loop here? Afaics this is only > called from process context, so the normal wait_for macro should be good > enough ... > -Daniel I agree, the reason why i did the _atomic as we observed delay in scheduling the wait_for and we ended up spending lot of time here. I will wait for other comments, If i dont get any, I will address this comment and submit the patch. >> + I915_READ(VLV_GTLC_SURVIVABILITY_REG)) != 0), 5)) { >> + DRM_ERROR("GFX_CLK_ON request timed out\n"); >> + return; >> + } >> + >> + vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ, dev_priv->rps.min_delay); >> + >> + if (wait_for_atomic(((vlv_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS)) >> + & GENFREQSTATUS) == 0, 5)) >> + DRM_DEBUG_DRIVER("timed out waiting for Punit\n"); >> + >> + /* Release the Gfx clock */ >> + I915_WRITE(VLV_GTLC_SURVIVABILITY_REG, >> + I915_READ(VLV_GTLC_SURVIVABILITY_REG) & >> + ~VLV_GFX_CLK_FORCE_ON_BIT); >> + >> + /* Unmask Turbo interrupts */ >> + I915_WRITE(GEN6_PMINTRMSK, ~(GEN6_PM_RPS_EVENTS | >> + GEN6_PM_RP_UP_EI_EXPIRED)); >> +} >> + >> + >> + >> void gen6_rps_idle(struct drm_i915_private *dev_priv) >> { >> struct drm_device *dev = dev_priv->dev; >> @@ -3042,7 +3092,7 @@ void gen6_rps_idle(struct drm_i915_private *dev_priv) >> mutex_lock(&dev_priv->rps.hw_lock); >> if (dev_priv->rps.enabled) { >> if (IS_VALLEYVIEW(dev)) >> - valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_delay); >> + vlv_set_rps_idle(dev_priv); >> else >> gen6_set_rps(dev_priv->dev, dev_priv->rps.min_delay); >> dev_priv->rps.last_adj = 0; >> @@ -4273,6 +4323,7 @@ void intel_gpu_ips_teardown(void) >> i915_mch_dev = NULL; >> spin_unlock_irq(&mchdev_lock); >> } >> + >> static void intel_init_emon(struct drm_device *dev) >> { >> struct drm_i915_private *dev_priv = dev->dev_private; >> -- >> 1.8.5.2 >> >> _______________________________________________ >> Intel-gfx mailing list >> Intel-gfx@lists.freedesktop.org >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx >