Merge branches 'clockevents/4.4-fixes' and 'clockevents/4.5-fixes' of http://git.linaro.org/people/daniel.lezcano/linux into timers/urgent

Pull in fixes from Daniel Lezcano:

 - Fix the vt8500 timer leading to a system lock up when dealing with too
   small delta (Roman Volkov)

 - Select the CLKSRC_MMIO when the fsl_ftm_timer is enabled with COMPILE_TEST
   (Daniel Lezcano)

 - Prevent to compile timers using the 'iomem' API when the architecture has
   not HAS_IOMEM set (Richard Weinberger)

1 files changed, 47 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 1618e2294a16..e23843f4d877 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -611,13 +611,59 @@ void amdgpu_driver_preclose_kms(struct drm_device *dev,
 u32 amdgpu_get_vblank_counter_kms(struct drm_device *dev, unsigned int pipe)
 {
         struct amdgpu_device *adev = dev->dev_private;
+        int vpos, hpos, stat;
+        u32 count;
 
         if (pipe >= adev->mode_info.num_crtc) {
                 DRM_ERROR("Invalid crtc %u\n", pipe);
                 return -EINVAL;
         }
 
-        return amdgpu_display_vblank_get_counter(adev, pipe);
+        /* The hw increments its frame counter at start of vsync, not at start
+         * of vblank, as is required by DRM core vblank counter handling.
+         * Cook the hw count here to make it appear to the caller as if it
+         * incremented at start of vblank. We measure distance to start of
+         * vblank in vpos. vpos therefore will be >= 0 between start of vblank
+         * and start of vsync, so vpos >= 0 means to bump the hw frame counter
+         * result by 1 to give the proper appearance to caller.
+         */
+        if (adev->mode_info.crtcs[pipe]) {
+                /* Repeat readout if needed to provide stable result if
+                 * we cross start of vsync during the queries.
+                 */
+                do {
+                        count = amdgpu_display_vblank_get_counter(adev, pipe);
+                        /* Ask amdgpu_get_crtc_scanoutpos to return vpos as
+                         * distance to start of vblank, instead of regular
+                         * vertical scanout pos.
+                         */
+                        stat = amdgpu_get_crtc_scanoutpos(
+                                dev, pipe, GET_DISTANCE_TO_VBLANKSTART,
+                                &vpos, &hpos, NULL, NULL,
+                                &adev->mode_info.crtcs[pipe]->base.hwmode);
+                } while (count != amdgpu_display_vblank_get_counter(adev, pipe));
+
+                if (((stat & (DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_ACCURATE)) !=
+                    (DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_ACCURATE))) {
+                        DRM_DEBUG_VBL("Query failed! stat %d\n", stat);
+                } else {
+                        DRM_DEBUG_VBL("crtc %d: dist from vblank start %d\n",
+                                      pipe, vpos);
+
+                        /* Bump counter if we are at >= leading edge of vblank,
+                         * but before vsync where vpos would turn negative and
+                         * the hw counter really increments.
+                         */
+                        if (vpos >= 0)
+                                count++;
+                }
+        } else {
+                /* Fallback to use value as is. */
+                count = amdgpu_display_vblank_get_counter(adev, pipe);
+                DRM_DEBUG_VBL("NULL mode info! Returned count may be wrong.\n");
+        }
+
+        return count;
 }
 
 /**