drm/vblank: Switch drm_driver->get_vblank_timestamp to return a bool

There's really no reason for anything more:
- Calling this while the crtc vblank stuff isn't set up is a driver
  bug. Those places alrready DRM_ERROR.
- Calling this when the crtc is off is either a driver bug (calling
  drm_crtc_handle_vblank at the wrong time) or a core bug (for
  anything else). Again, we DRM_ERROR.
- EINVAL is checked at higher levels already, and if we'd use struct
  drm_crtc * instead of (dev, pipe) it would be real obvious that
  those are again core bugs.

The only valid failure mode is crap hardware that couldn't sample a
useful timestamp, to ask the core to just grab a not-so-accurate
timestamp. Bool is perfectly fine for that.

v2: Also fix up the one caller, I lost that in the shuffling (Jani).

v3: Fixup commit message (Neil).

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170509140329.24114-1-daniel.vetter@ffwll.ch

11 files changed, 56 insertions, 69 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 6a8129949333..7b4f808afff9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1910,10 +1910,10 @@ int amdgpu_device_resume(struct drm_device *dev, bool resume, bool fbcon);
 u32 amdgpu_get_vblank_counter_kms(struct drm_device *dev, unsigned int pipe);
 int amdgpu_enable_vblank_kms(struct drm_device *dev, unsigned int pipe);
 void amdgpu_disable_vblank_kms(struct drm_device *dev, unsigned int pipe);
-int amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
-                                    int *max_error,
-                                    struct timeval *vblank_time,
-                                    unsigned flags);
+bool amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
+                                     int *max_error,
+                                     struct timeval *vblank_time,
+                                     unsigned flags);
 long amdgpu_kms_compat_ioctl(struct file *filp, unsigned int cmd,
                              unsigned long arg);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 832be632478f..a1b97809305e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -945,19 +945,19 @@ void amdgpu_disable_vblank_kms(struct drm_device *dev, unsigned int pipe)
  *
  * Gets the timestamp on the requested crtc based on the
  * scanout position.  (all asics).
- * Returns postive status flags on success, negative error on failure.
+ * Returns true on success, false on failure.
  */
-int amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
-                                    int *max_error,
-                                    struct timeval *vblank_time,
-                                    unsigned flags)
+bool amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
+                                     int *max_error,
+                                     struct timeval *vblank_time,
+                                     unsigned flags)
 {
         struct drm_crtc *crtc;
         struct amdgpu_device *adev = dev->dev_private;
 
         if (pipe >= dev->num_crtcs) {
                 DRM_ERROR("Invalid crtc %u\n", pipe);
-                return -EINVAL;
+                return false;
         }
 
         /* Get associated drm_crtc: */
@@ -966,7 +966,7 @@ int amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
                 /* This can occur on driver load if some component fails to
                  * initialize completely and driver is unloaded */
                 DRM_ERROR("Uninitialized crtc %d\n", pipe);
-                return -EINVAL;
+                return false;
         }
 
         /* Helper routine in DRM core does all the work: */
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 8c866cac62dd..677b37b0372b 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -724,43 +724,32 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
  * active. Higher level code is expected to handle this.
  *
  * Returns:
- * Negative value on error, failure or if not supported in current
- * video mode:
- *
- * -EINVAL    Invalid CRTC.
- * -EAGAIN    Temporary unavailable, e.g., called before initial modeset.
- * -ENOTSUPP  Function not supported in current display mode.
- * -EIO       Failed, e.g., due to failed scanout position query.
- *
- * Returns or'ed positive status flags on success:
- *
- * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
- * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
  *
+ * Returns true on success, and false on failure, i.e. when no accurate
+ * timestamp could be acquired.
  */
-int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
-                                          unsigned int pipe,
-                                          int *max_error,
-                                          struct timeval *vblank_time,
-                                          unsigned flags,
-                                          const struct drm_display_mode *mode)
+bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
+                                           unsigned int pipe,
+                                           int *max_error,
+                                           struct timeval *vblank_time,
+                                           unsigned flags,
+                                           const struct drm_display_mode *mode)
 {
         struct timeval tv_etime;
         ktime_t stime, etime;
         unsigned int vbl_status;
-        int ret = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
         int vpos, hpos, i;
         int delta_ns, duration_ns;
 
         if (pipe >= dev->num_crtcs) {
                 DRM_ERROR("Invalid crtc %u\n", pipe);
-                return -EINVAL;
+                return false;
         }
 
         /* Scanout position query not supported? Should not happen. */
         if (!dev->driver->get_scanout_position) {
                 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
-                return -EIO;
+                return false;
         }
 
         /* If mode timing undefined, just return as no-op:
@@ -768,7 +757,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
          */
         if (mode->crtc_clock == 0) {
                 DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
-                return -EAGAIN;
+                return false;
         }
 
         /* Get current scanout position with system timestamp.
@@ -792,7 +781,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
                 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
                         DRM_DEBUG("crtc %u : scanoutpos query failed [0x%x].\n",
                                   pipe, vbl_status);
-                        return -EIO;
+                        return false;
                 }
 
                 /* Compute uncertainty in timestamp of scanout position query. */
@@ -836,7 +825,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
                       (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
                       duration_ns/1000, i);
 
-        return ret;
+        return true;
 }
 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
 
@@ -872,25 +861,23 @@ static bool
 drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
                           struct timeval *tvblank, unsigned flags)
 {
-        int ret;
+        bool ret = false;
 
         /* Define requested maximum error on timestamps (nanoseconds). */
         int max_error = (int) drm_timestamp_precision * 1000;
 
         /* Query driver if possible and precision timestamping enabled. */
-        if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
+        if (dev->driver->get_vblank_timestamp && (max_error > 0))
                 ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
                                                         tvblank, flags);
-                if (ret > 0)
-                        return true;
-        }
 
         /* GPU high precision timestamp query unsupported or failed.
          * Return current monotonic/gettimeofday timestamp as best estimate.
          */
-        *tvblank = get_drm_timestamp();
+        if (!ret)
+                *tvblank = get_drm_timestamp();
 
-        return false;
+        return ret;
 }
 
 /**
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index fd97fe00cd0d..315e6876fa85 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -964,7 +964,7 @@ int intel_get_crtc_scanline(struct intel_crtc *crtc)
         return position;
 }
 
-static int i915_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
+static bool i915_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
                               int *max_error,
                               struct timeval *vblank_time,
                               unsigned flags)
@@ -974,19 +974,19 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
 
         if (pipe >= INTEL_INFO(dev_priv)->num_pipes) {
                 DRM_ERROR("Invalid crtc %u\n", pipe);
-                return -EINVAL;
+                return false;
         }
 
         /* Get drm_crtc to timestamp: */
         crtc = intel_get_crtc_for_pipe(dev_priv, pipe);
         if (crtc == NULL) {
                 DRM_ERROR("Invalid crtc %u\n", pipe);
-                return -EINVAL;
+                return false;
         }
 
         if (!crtc->base.hwmode.crtc_clock) {
                 DRM_DEBUG_KMS("crtc %u is disabled\n", pipe);
-                return -EBUSY;
+                return false;
         }
 
         /* Helper routine in DRM core does all the work: */
diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
index d3d6b4cae1e6..ffeb34bee3af 100644
--- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
@@ -592,23 +592,23 @@ static int mdp5_get_scanoutpos(struct drm_device *dev, unsigned int pipe,
         return ret;
 }
 
-static int mdp5_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
-                                     int *max_error,
-                                     struct timeval *vblank_time,
-                                     unsigned flags)
+static bool mdp5_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
+                                      int *max_error,
+                                      struct timeval *vblank_time,
+                                      unsigned flags)
 {
         struct msm_drm_private *priv = dev->dev_private;
         struct drm_crtc *crtc;
 
         if (pipe < 0 || pipe >= priv->num_crtcs) {
                 DRM_ERROR("Invalid crtc %d\n", pipe);
-                return -EINVAL;
+                return false;
         }
 
         crtc = priv->crtcs[pipe];
         if (!crtc) {
                 DRM_ERROR("Invalid crtc %d\n", pipe);
-                return -EINVAL;
+                return false;
         }
 
         return drm_calc_vbltimestamp_from_scanoutpos(dev, pipe, max_error,
diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c
index 21b10f9840c9..f1e36f70755d 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.c
+++ b/drivers/gpu/drm/nouveau/nouveau_display.c
@@ -156,7 +156,7 @@ nouveau_display_scanoutpos(struct drm_device *dev, unsigned int pipe,
         return 0;
 }
 
-int
+bool
 nouveau_display_vblstamp(struct drm_device *dev, unsigned int pipe,
                          int *max_error, struct timeval *time, unsigned flags)
 {
@@ -174,7 +174,7 @@ nouveau_display_vblstamp(struct drm_device *dev, unsigned int pipe,
                 }
         }
 
-        return -EINVAL;
+        return false;
 }
 
 static void
diff --git a/drivers/gpu/drm/nouveau/nouveau_display.h b/drivers/gpu/drm/nouveau/nouveau_display.h
index e1d772d39488..c6bfe533a641 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.h
+++ b/drivers/gpu/drm/nouveau/nouveau_display.h
@@ -71,8 +71,8 @@ void nouveau_display_vblank_disable(struct drm_device *, unsigned int);
 int  nouveau_display_scanoutpos(struct drm_device *, unsigned int,
                                 unsigned int, int *, int *, ktime_t *,
                                 ktime_t *, const struct drm_display_mode *);
-int  nouveau_display_vblstamp(struct drm_device *, unsigned int, int *,
-                              struct timeval *, unsigned);
+bool  nouveau_display_vblstamp(struct drm_device *, unsigned int, int *,
+                               struct timeval *, unsigned);
 
 int  nouveau_crtc_page_flip(struct drm_crtc *crtc, struct drm_framebuffer *fb,
                             struct drm_pending_vblank_event *event,
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 93d45aa5c3d4..caa0b1cc4269 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -115,10 +115,10 @@ int radeon_resume_kms(struct drm_device *dev, bool resume, bool fbcon);
 u32 radeon_get_vblank_counter_kms(struct drm_device *dev, unsigned int pipe);
 int radeon_enable_vblank_kms(struct drm_device *dev, unsigned int pipe);
 void radeon_disable_vblank_kms(struct drm_device *dev, unsigned int pipe);
-int radeon_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
-                                    int *max_error,
-                                    struct timeval *vblank_time,
-                                    unsigned flags);
+bool radeon_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
+                                     int *max_error,
+                                     struct timeval *vblank_time,
+                                     unsigned flags);
 void radeon_driver_irq_preinstall_kms(struct drm_device *dev);
 int radeon_driver_irq_postinstall_kms(struct drm_device *dev);
 void radeon_driver_irq_uninstall_kms(struct drm_device *dev);
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index e3e7cb1d10a2..535969d74f64 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -869,25 +869,25 @@ void radeon_disable_vblank_kms(struct drm_device *dev, int crtc)
  *
  * Gets the timestamp on the requested crtc based on the
  * scanout position.  (all asics).
- * Returns postive status flags on success, negative error on failure.
+ * Returns true on success, false on failure.
  */
-int radeon_get_vblank_timestamp_kms(struct drm_device *dev, int crtc,
-                                    int *max_error,
-                                    struct timeval *vblank_time,
-                                    unsigned flags)
+bool radeon_get_vblank_timestamp_kms(struct drm_device *dev, int crtc,
+                                     int *max_error,
+                                     struct timeval *vblank_time,
+                                     unsigned flags)
 {
         struct drm_crtc *drmcrtc;
         struct radeon_device *rdev = dev->dev_private;
 
         if (crtc < 0 || crtc >= dev->num_crtcs) {
                 DRM_ERROR("Invalid crtc %d\n", crtc);
-                return -EINVAL;
+                return false;
         }
 
         /* Get associated drm_crtc: */
         drmcrtc = &rdev->mode_info.crtcs[crtc]->base;
         if (!drmcrtc)
-                return -EINVAL;
+                return false;
 
         /* Helper routine in DRM core does all the work: */
         return drm_calc_vbltimestamp_from_scanoutpos(dev, crtc, max_error,
diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index d86c8cce3182..f506525a1066 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -270,7 +270,7 @@ int vc4_crtc_get_scanoutpos(struct drm_device *dev, unsigned int crtc_id,
         return ret;
 }
 
-int vc4_crtc_get_vblank_timestamp(struct drm_device *dev, unsigned int crtc_id,
+bool vc4_crtc_get_vblank_timestamp(struct drm_device *dev, unsigned int crtc_id,
                                   int *max_error, struct timeval *vblank_time,
                                   unsigned flags)
 {
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 92eb7d811bf2..d1c53a5d0923 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -493,7 +493,7 @@ int vc4_crtc_get_scanoutpos(struct drm_device *dev, unsigned int crtc_id,
                             unsigned int flags, int *vpos, int *hpos,
                             ktime_t *stime, ktime_t *etime,
                             const struct drm_display_mode *mode);
-int vc4_crtc_get_vblank_timestamp(struct drm_device *dev, unsigned int crtc_id,
+bool vc4_crtc_get_vblank_timestamp(struct drm_device *dev, unsigned int crtc_id,
                                   int *max_error, struct timeval *vblank_time,
                                   unsigned flags);