tree: https://github.com/vsyrjala/linux.git vrr_fixes head: b9b43deb7fc52a06855bc7d4918d704381fb2d61 commit: 0ff0a6ee139b6d7d414c0125ddc6b7ba1159ed40 [23/26] drm/i915: Fix vblank timestamps with VRR config: x86_64-randconfig-m001-20201215 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; smatch warnings: drivers/gpu/drm/i915/i915_irq.c:891 i915_get_crtc_scanoutpos() warn: inconsistent indenting vim +891 drivers/gpu/drm/i915/i915_irq.c 828 829 static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc, 830 bool in_vblank_irq, 831 int *vpos, int *hpos, 832 ktime_t *stime, ktime_t *etime, 833 const struct drm_display_mode *mode) 834 { 835 struct drm_device *dev = _crtc->dev; 836 struct drm_i915_private *dev_priv = to_i915(dev); 837 struct intel_crtc *crtc = to_intel_crtc(_crtc); 838 enum pipe pipe = crtc->pipe; 839 int position; 840 int vbl_start, vbl_end, hsync_start, htotal, vtotal; 841 unsigned long irqflags; 842 bool use_scanline_counter = INTEL_GEN(dev_priv) >= 5 || 843 IS_G4X(dev_priv) || IS_GEN(dev_priv, 2) || 844 crtc->mode_flags & I915_MODE_FLAG_USE_SCANLINE_COUNTER; 845 846 if (drm_WARN_ON(&dev_priv->drm, !mode->crtc_clock)) { 847 drm_dbg(&dev_priv->drm, 848 "trying to get scanoutpos for disabled " 849 "pipe %c\n", pipe_name(pipe)); 850 return false; 851 } 852 853 htotal = mode->crtc_htotal; 854 hsync_start = mode->crtc_hsync_start; 855 vtotal = mode->crtc_vtotal; 856 vbl_start = mode->crtc_vblank_start; 857 vbl_end = mode->crtc_vblank_end; 858 859 if (mode->flags & DRM_MODE_FLAG_INTERLACE) { 860 vbl_start = DIV_ROUND_UP(vbl_start, 2); 861 vbl_end /= 2; 862 vtotal /= 2; 863 } 864 865 /* 866 * Lock uncore.lock, as we will do multiple timing critical raw 867 * register reads, potentially with preemption disabled, so the 868 * following code must not block on uncore.lock. 869 */ 870 spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); 871 872 /* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */ 873 874 /* Get optional system timestamp before query. */ 875 if (stime) 876 *stime = ktime_get(); 877 878 if (crtc->mode_flags & I915_MODE_FLAG_VRR) { 879 int scanlines = intel_crtc_scanlines_since_frame_timestamp(crtc); 880 881 position = __intel_get_crtc_scanline(crtc); 882 883 /* 884 * Already exiting vblank? If so, shift our position 885 * so it looks like we're already apporaching the full 886 * vblank end. This should make the generated timestamp 887 * more or less match when the active portion will start. 888 */ 889 if (position >= vbl_start && scanlines < position) 890 position = min(crtc->vmax_vblank_start + scanlines, vtotal - 1); 892 /* No obvious pixelcount register. Only query vertical 893 * scanout position from Display scan line register. 894 */ 895 position = __intel_get_crtc_scanline(crtc); 896 } else { 897 /* Have access to pixelcount since start of frame. 898 * We can split this into vertical and horizontal 899 * scanout position. 900 */ 901 position = (intel_de_read_fw(dev_priv, PIPEFRAMEPIXEL(pipe)) & PIPE_PIXEL_MASK) >> PIPE_PIXEL_SHIFT; 902 903 /* convert to pixel counts */ 904 vbl_start *= htotal; 905 vbl_end *= htotal; 906 vtotal *= htotal; 907 908 /* 909 * In interlaced modes, the pixel counter counts all pixels, 910 * so one field will have htotal more pixels. In order to avoid 911 * the reported position from jumping backwards when the pixel 912 * counter is beyond the length of the shorter field, just 913 * clamp the position the length of the shorter field. This 914 * matches how the scanline counter based position works since 915 * the scanline counter doesn't count the two half lines. 916 */ 917 if (position >= vtotal) 918 position = vtotal - 1; 919 920 /* 921 * Start of vblank interrupt is triggered at start of hsync, 922 * just prior to the first active line of vblank. However we 923 * consider lines to start at the leading edge of horizontal 924 * active. So, should we get here before we've crossed into 925 * the horizontal active of the first line in vblank, we would 926 * not set the DRM_SCANOUTPOS_INVBL flag. In order to fix that, 927 * always add htotal-hsync_start to the current pixel position. 928 */ 929 position = (position + htotal - hsync_start) % vtotal; 930 } 931 932 /* Get optional system timestamp after query. */ 933 if (etime) 934 *etime = ktime_get(); 935 936 /* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */ 937 938 spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); 939 940 /* 941 * While in vblank, position will be negative 942 * counting up towards 0 at vbl_end. And outside 943 * vblank, position will be positive counting 944 * up since vbl_end. 945 */ 946 if (position >= vbl_start) 947 position -= vbl_end; 948 else 949 position += vtotal - vbl_end; 950 951 if (use_scanline_counter) { 952 *vpos = position; 953 *hpos = 0; 954 } else { 955 *vpos = position / htotal; 956 *hpos = position - (*vpos * htotal); 957 } 958 959 return true; 960 } 961 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org