cregit-Linux how code gets into the kernel

Release 4.7 drivers/gpu/drm/i915/intel_fifo_underrun.c

/*
 * Copyright © 2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Daniel Vetter <daniel.vetter@ffwll.ch>
 *
 */

#include "i915_drv.h"
#include "intel_drv.h"

/**
 * DOC: fifo underrun handling
 *
 * The i915 driver checks for display fifo underruns using the interrupt signals
 * provided by the hardware. This is enabled by default and fairly useful to
 * debug display issues, especially watermark settings.
 *
 * If an underrun is detected this is logged into dmesg. To avoid flooding logs
 * and occupying the cpu underrun interrupts are disabled after the first
 * occurrence until the next modeset on a given pipe.
 *
 * Note that underrun detection on gmch platforms is a bit more ugly since there
 * is no interrupt (despite that the signalling bit is in the PIPESTAT pipe
 * interrupt register). Also on some other platforms underrun interrupts are
 * shared, which means that if we detect an underrun we need to disable underrun
 * reporting on all pipes.
 *
 * The code also supports underrun detection on the PCH transcoder.
 */


static bool ivb_can_enable_err_int(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; struct intel_crtc *crtc; enum pipe pipe; assert_spin_locked(&dev_priv->irq_lock); for_each_pipe(dev_priv, pipe) { crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]); if (crtc->cpu_fifo_underrun_disabled) return false; } return true; }

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static bool cpt_can_enable_serr_int(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; enum pipe pipe; struct intel_crtc *crtc; assert_spin_locked(&dev_priv->irq_lock); for_each_pipe(dev_priv, pipe) { crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]); if (crtc->pch_fifo_underrun_disabled) return false; } return true; }

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static void i9xx_check_fifo_underruns(struct intel_crtc *crtc) { struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); i915_reg_t reg = PIPESTAT(crtc->pipe); u32 pipestat = I915_READ(reg) & 0xffff0000; assert_spin_locked(&dev_priv->irq_lock); if ((pipestat & PIPE_FIFO_UNDERRUN_STATUS) == 0) return; I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS); POSTING_READ(reg); DRM_ERROR("pipe %c underrun\n", pipe_name(crtc->pipe)); }

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static void i9xx_set_fifo_underrun_reporting(struct drm_device *dev, enum pipe pipe, bool enable, bool old) { struct drm_i915_private *dev_priv = dev->dev_private; i915_reg_t reg = PIPESTAT(pipe); u32 pipestat = I915_READ(reg) & 0xffff0000; assert_spin_locked(&dev_priv->irq_lock); if (enable) { I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS); POSTING_READ(reg); } else { if (old && pipestat & PIPE_FIFO_UNDERRUN_STATUS) DRM_ERROR("pipe %c underrun\n", pipe_name(pipe)); } }

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static void ironlake_set_fifo_underrun_reporting(struct drm_device *dev, enum pipe pipe, bool enable) { struct drm_i915_private *dev_priv = dev->dev_private; uint32_t bit = (pipe == PIPE_A) ? DE_PIPEA_FIFO_UNDERRUN : DE_PIPEB_FIFO_UNDERRUN; if (enable) ilk_enable_display_irq(dev_priv, bit); else ilk_disable_display_irq(dev_priv, bit); }

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static void ivybridge_check_fifo_underruns(struct intel_crtc *crtc) { struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); enum pipe pipe = crtc->pipe; uint32_t err_int = I915_READ(GEN7_ERR_INT); assert_spin_locked(&dev_priv->irq_lock); if ((err_int & ERR_INT_FIFO_UNDERRUN(pipe)) == 0) return; I915_WRITE(GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe)); POSTING_READ(GEN7_ERR_INT); DRM_ERROR("fifo underrun on pipe %c\n", pipe_name(pipe)); }

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static void ivybridge_set_fifo_underrun_reporting(struct drm_device *dev, enum pipe pipe, bool enable, bool old) { struct drm_i915_private *dev_priv = dev->dev_private; if (enable) { I915_WRITE(GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe)); if (!ivb_can_enable_err_int(dev)) return; ilk_enable_display_irq(dev_priv, DE_ERR_INT_IVB); } else { ilk_disable_display_irq(dev_priv, DE_ERR_INT_IVB); if (old && I915_READ(GEN7_ERR_INT) & ERR_INT_FIFO_UNDERRUN(pipe)) { DRM_ERROR("uncleared fifo underrun on pipe %c\n", pipe_name(pipe)); } } }

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static void broadwell_set_fifo_underrun_reporting(struct drm_device *dev, enum pipe pipe, bool enable) { struct drm_i915_private *dev_priv = dev->dev_private; if (enable) bdw_enable_pipe_irq(dev_priv, pipe, GEN8_PIPE_FIFO_UNDERRUN); else bdw_disable_pipe_irq(dev_priv, pipe, GEN8_PIPE_FIFO_UNDERRUN); }

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static void ibx_set_fifo_underrun_reporting(struct drm_device *dev, enum transcoder pch_transcoder, bool enable) { struct drm_i915_private *dev_priv = dev->dev_private; uint32_t bit = (pch_transcoder == TRANSCODER_A) ? SDE_TRANSA_FIFO_UNDER : SDE_TRANSB_FIFO_UNDER; if (enable) ibx_enable_display_interrupt(dev_priv, bit); else ibx_disable_display_interrupt(dev_priv, bit); }

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static void cpt_check_pch_fifo_underruns(struct intel_crtc *crtc) { struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); enum transcoder pch_transcoder = (enum transcoder) crtc->pipe; uint32_t serr_int = I915_READ(SERR_INT); assert_spin_locked(&dev_priv->irq_lock); if ((serr_int & SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) == 0) return; I915_WRITE(SERR_INT, SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)); POSTING_READ(SERR_INT); DRM_ERROR("pch fifo underrun on pch transcoder %s\n", transcoder_name(pch_transcoder)); }

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static void cpt_set_fifo_underrun_reporting(struct drm_device *dev, enum transcoder pch_transcoder, bool enable, bool old) { struct drm_i915_private *dev_priv = dev->dev_private; if (enable) { I915_WRITE(SERR_INT, SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)); if (!cpt_can_enable_serr_int(dev)) return; ibx_enable_display_interrupt(dev_priv, SDE_ERROR_CPT); } else { ibx_disable_display_interrupt(dev_priv, SDE_ERROR_CPT); if (old && I915_READ(SERR_INT) & SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) { DRM_ERROR("uncleared pch fifo underrun on pch transcoder %s\n", transcoder_name(pch_transcoder)); } } }

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static bool __intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev, enum pipe pipe, bool enable) { struct drm_i915_private *dev_priv = dev->dev_private; struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe]; struct intel_crtc *intel_crtc = to_intel_crtc(crtc); bool old; assert_spin_locked(&dev_priv->irq_lock); old = !intel_crtc->cpu_fifo_underrun_disabled; intel_crtc->cpu_fifo_underrun_disabled = !enable; if (HAS_GMCH_DISPLAY(dev)) i9xx_set_fifo_underrun_reporting(dev, pipe, enable, old); else if (IS_GEN5(dev) || IS_GEN6(dev)) ironlake_set_fifo_underrun_reporting(dev, pipe, enable); else if (IS_GEN7(dev)) ivybridge_set_fifo_underrun_reporting(dev, pipe, enable, old); else if (IS_GEN8(dev) || IS_GEN9(dev)) broadwell_set_fifo_underrun_reporting(dev, pipe, enable); return old; }

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/** * intel_set_cpu_fifo_underrun_reporting - set cpu fifo underrrun reporting state * @dev_priv: i915 device instance * @pipe: (CPU) pipe to set state for * @enable: whether underruns should be reported or not * * This function sets the fifo underrun state for @pipe. It is used in the * modeset code to avoid false positives since on many platforms underruns are * expected when disabling or enabling the pipe. * * Notice that on some platforms disabling underrun reports for one pipe * disables for all due to shared interrupts. Actual reporting is still per-pipe * though. * * Returns the previous state of underrun reporting. */
bool intel_set_cpu_fifo_underrun_reporting(struct drm_i915_private *dev_priv, enum pipe pipe, bool enable) { unsigned long flags; bool ret; spin_lock_irqsave(&dev_priv->irq_lock, flags); ret = __intel_set_cpu_fifo_underrun_reporting(dev_priv->dev, pipe, enable); spin_unlock_irqrestore(&dev_priv->irq_lock, flags); return ret; }

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/** * intel_set_pch_fifo_underrun_reporting - set PCH fifo underrun reporting state * @dev_priv: i915 device instance * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older) * @enable: whether underruns should be reported or not * * This function makes us disable or enable PCH fifo underruns for a specific * PCH transcoder. Notice that on some PCHs (e.g. CPT/PPT), disabling FIFO * underrun reporting for one transcoder may also disable all the other PCH * error interruts for the other transcoders, due to the fact that there's just * one interrupt mask/enable bit for all the transcoders. * * Returns the previous state of underrun reporting. */
bool intel_set_pch_fifo_underrun_reporting(struct drm_i915_private *dev_priv, enum transcoder pch_transcoder, bool enable) { struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pch_transcoder]; struct intel_crtc *intel_crtc = to_intel_crtc(crtc); unsigned long flags; bool old; /* * NOTE: Pre-LPT has a fixed cpu pipe -> pch transcoder mapping, but LPT * has only one pch transcoder A that all pipes can use. To avoid racy * pch transcoder -> pipe lookups from interrupt code simply store the * underrun statistics in crtc A. Since we never expose this anywhere * nor use it outside of the fifo underrun code here using the "wrong" * crtc on LPT won't cause issues. */ spin_lock_irqsave(&dev_priv->irq_lock, flags); old = !intel_crtc->pch_fifo_underrun_disabled; intel_crtc->pch_fifo_underrun_disabled = !enable; if (HAS_PCH_IBX(dev_priv)) ibx_set_fifo_underrun_reporting(dev_priv->dev, pch_transcoder, enable); else cpt_set_fifo_underrun_reporting(dev_priv->dev, pch_transcoder, enable, old); spin_unlock_irqrestore(&dev_priv->irq_lock, flags); return old; }

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/** * intel_cpu_fifo_underrun_irq_handler - handle CPU fifo underrun interrupt * @dev_priv: i915 device instance * @pipe: (CPU) pipe to set state for * * This handles a CPU fifo underrun interrupt, generating an underrun warning * into dmesg if underrun reporting is enabled and then disables the underrun * interrupt to avoid an irq storm. */
void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv, enum pipe pipe) { struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe]; /* We may be called too early in init, thanks BIOS! */ if (crtc == NULL) return; /* GMCH can't disable fifo underruns, filter them. */ if (HAS_GMCH_DISPLAY(dev_priv) && to_intel_crtc(crtc)->cpu_fifo_underrun_disabled) return; if (intel_set_cpu_fifo_underrun_reporting(dev_priv, pipe, false)) DRM_ERROR("CPU pipe %c FIFO underrun\n", pipe_name(pipe)); }

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/** * intel_pch_fifo_underrun_irq_handler - handle PCH fifo underrun interrupt * @dev_priv: i915 device instance * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older) * * This handles a PCH fifo underrun interrupt, generating an underrun warning * into dmesg if underrun reporting is enabled and then disables the underrun * interrupt to avoid an irq storm. */
void intel_pch_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv, enum transcoder pch_transcoder) { if (intel_set_pch_fifo_underrun_reporting(dev_priv, pch_transcoder, false)) DRM_ERROR("PCH transcoder %s FIFO underrun\n", transcoder_name(pch_transcoder)); }

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/** * intel_check_cpu_fifo_underruns - check for CPU fifo underruns immediately * @dev_priv: i915 device instance * * Check for CPU fifo underruns immediately. Useful on IVB/HSW where the shared * error interrupt may have been disabled, and so CPU fifo underruns won't * necessarily raise an interrupt, and on GMCH platforms where underruns never * raise an interrupt. */
void intel_check_cpu_fifo_underruns(struct drm_i915_private *dev_priv) { struct intel_crtc *crtc; spin_lock_irq(&dev_priv->irq_lock); for_each_intel_crtc(dev_priv->dev, crtc) { if (crtc->cpu_fifo_underrun_disabled) continue; if (HAS_GMCH_DISPLAY(dev_priv)) i9xx_check_fifo_underruns(crtc); else if (IS_GEN7(dev_priv)) ivybridge_check_fifo_underruns(crtc); } spin_unlock_irq(&dev_priv->irq_lock); }

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/** * intel_check_pch_fifo_underruns - check for PCH fifo underruns immediately * @dev_priv: i915 device instance * * Check for PCH fifo underruns immediately. Useful on CPT/PPT where the shared * error interrupt may have been disabled, and so PCH fifo underruns won't * necessarily raise an interrupt. */
void intel_check_pch_fifo_underruns(struct drm_i915_private *dev_priv) { struct intel_crtc *crtc; spin_lock_irq(&dev_priv->irq_lock); for_each_intel_crtc(dev_priv->dev, crtc) { if (crtc->pch_fifo_underrun_disabled) continue; if (HAS_PCH_CPT(dev_priv)) cpt_check_pch_fifo_underruns(crtc); } spin_unlock_irq(&dev_priv->irq_lock); }

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