[PATCH 01/23] drm: Add get_scanout_position() to struct drm_crtc_helper_funcs

Yannick FERTRE yannick.fertre at st.com
Tue Jan 14 15:31:25 UTC 2020


Thanks for the patch.

Tested-by: Yannick Fertré <yannick.fertre at st.com><mailto:yannick.fertre at st.com>

BR
Yannick Fertré


On 1/10/20 10:21 AM, Thomas Zimmermann wrote:

The new callback get_scanout_position() reads the current location of
the scanout process. The operation is currentyl located in struct
drm_driver, but really belongs to the CRTC. Drivers will be converted
in separate patches.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de><mailto:tzimmermann at suse.de>
---
 drivers/gpu/drm/drm_vblank.c             | 24 ++++++++----
 include/drm/drm_drv.h                    |  7 +---
 include/drm/drm_modeset_helper_vtables.h | 47 ++++++++++++++++++++++++
 3 files changed, 65 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 1659b13b178c..c12f0b333e14 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -30,6 +30,7 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_framebuffer.h>
+#include <drm/drm_modeset_helper_vtables.h>
 #include <drm/drm_print.h>
 #include <drm/drm_vblank.h>

@@ -590,7 +591,7 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
  * Implements calculation of exact vblank timestamps from given drm_display_mode
  * timings and current video scanout position of a CRTC. This can be directly
  * used as the &drm_driver.get_vblank_timestamp implementation of a kms driver
- * if &drm_driver.get_scanout_position is implemented.
+ * if &drm_crtc_helper_funcs.get_scanout_position is implemented.
  *
  * The current implementation only handles standard video modes. For double scan
  * and interlaced modes the driver is supposed to adjust the hardware mode
@@ -632,8 +633,9 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
        }

        /* 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");
+       if (!dev->driver->get_scanout_position ||
+           !crtc->helper_private->get_scanout_position) {
+               DRM_ERROR("Called from CRTC w/o get_scanout_position()!?\n");
                return false;
        }

@@ -664,11 +666,17 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
                 * Get vertical and horizontal scanout position vpos, hpos,
                 * and bounding timestamps stime, etime, pre/post query.
                 */
-               vbl_status = dev->driver->get_scanout_position(dev, pipe,
-                                                              in_vblank_irq,
-                                                              &vpos, &hpos,
-                                                              &stime, &etime,
-                                                              mode);
+               if (crtc->helper_private->get_scanout_position) {
+                       vbl_status =
+                               crtc->helper_private->get_scanout_position(
+                                       crtc, in_vblank_irq, &vpos, &hpos,
+                                       &stime, &etime, mode);
+               } else {
+                       vbl_status =
+                               dev->driver->get_scanout_position(
+                                       dev, pipe, in_vblank_irq, &vpos,
+                                       &hpos, &stime, &etime, mode);
+               }

                /* Return as no-op if scanout query unsupported or failed. */
                if (!vbl_status) {
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index cf13470810a5..d0049e5786fc 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -362,11 +362,8 @@ struct drm_driver {
         * True on success, false if a reliable scanout position counter could
         * not be read out.
         *
-        * FIXME:
-        *
-        * Since this is a helper to implement @get_vblank_timestamp, we should
-        * move it to &struct drm_crtc_helper_funcs, like all the other
-        * helper-internal hooks.
+        * This is deprecated and should not be used by new drivers.
+        * Use &drm_crtc_helper_funcs.get_scanout_position instead.
         */
        bool (*get_scanout_position) (struct drm_device *dev, unsigned int pipe,
                                      bool in_vblank_irq, int *vpos, int *hpos,
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index 5a87f1bd7a3f..e398512bfd5f 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -450,6 +450,53 @@ struct drm_crtc_helper_funcs {
         */
        void (*atomic_disable)(struct drm_crtc *crtc,
                               struct drm_crtc_state *old_crtc_state);
+
+       /**
+        * @get_scanout_position:
+        *
+        * Called by vblank timestamping code.
+        *
+        * Returns the current display scanout position from a CRTC and an
+        * optional accurate ktime_get() timestamp of when the position was
+        * measured. Note that this is a helper callback which is only used
+        * if a driver uses drm_calc_vbltimestamp_from_scanoutpos() for the
+        * @drm_driver.get_vblank_timestamp callback.
+        *
+        * Parameters:
+        *
+        * crtc:
+        *     The CRTC.
+        * in_vblank_irq:
+        *     True when called from drm_crtc_handle_vblank(). Some drivers
+        *     need to apply some workarounds for gpu-specific vblank irq
+        *     quirks if the flag is set.
+        * vpos:
+        *     Target location for current vertical scanout position.
+        * hpos:
+        *     Target location for current horizontal scanout position.
+        * stime:
+        *     Target location for timestamp taken immediately before
+        *     scanout position query. Can be NULL to skip timestamp.
+        * etime:
+        *     Target location for timestamp taken immediately after
+        *     scanout position query. Can be NULL to skip timestamp.
+        * mode:
+        *     Current display timings.
+        *
+        * Returns vpos as a positive number while in active scanout area.
+        * Returns vpos as a negative number inside vblank, counting the number
+        * of scanlines to go until end of vblank, e.g., -1 means "one scanline
+        * until start of active scanout / end of vblank."
+        *
+        * Returns:
+        *
+        * True on success, false if a reliable scanout position counter could
+        * not be read out.
+        */
+       bool (*get_scanout_position)(struct drm_crtc *crtc,
+                                    bool in_vblank_irq, int *vpos, int *hpos,
+                                    ktime_t *stime, ktime_t *etime,
+                                    const struct drm_display_mode *mode);
 };

 /**


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