Merge tag 'drm-misc-next-2020-04-14' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for 5.8:

UAPI Changes:

  - drm: error out with EBUSY when device has existing master
  - drm: rework SET_MASTER and DROP_MASTER perm handling

Cross-subsystem Changes:

  - mm: export two symbols from slub/slob
  - fbdev: savage: fix -Wextra build warning
  - video: omap2: Use scnprintf() for avoiding potential buffer overflow

Core Changes:

  - Remove drm_pci.h
  - drm_pci_{alloc/free)() are now legacy
  - Introduce managed DRM resourcesA
  - Allow drivers to subclass struct drm_framebuffer
  - Introduce struct drm_afbc_framebuffer and helpers
  - fbdev: remove return value from generic fbdev setup
  - Introduce simple-encoder helper
  - vram-helpers: set fence on plane
  - dp_mst: ACT timeout improvements
  - dp_mst: Remove drm_dp_mst_has_audio()
  - TTM: ttm_trace_dma_{map/unmap}() cleanups
  - dma-buf: add flag for PCIP2P support
  - EDID: Various improvements
  - Encoder: cleanup semantics of possible_clones and possible_crtcs
  - VBLANK documentation updates
  - Writeback documentation updates

Driver Changes:

  - Convert several drivers to i2c_new_client_device()
  - Drop explicit drm_mode_config_cleanup() calls from drivers
  - Auto-release device structures with drmm_add_final_kfree()
  - Init bfdev console after registering DRM device
  - Make various .debugfs functions return 0 unconditionally; ignore errors
  - video: Use scnprintf() to avoid buffer overflows
  - Convert drivers to simple encoders

  - drm/amdgpu: note that we can handle peer2peer DMA-buf
  - drm/amdgpu: add support for exporting VRAM using DMA-buf v3
  - drm/kirin: Revert change to register connectors
  - drm/lima: Add optional devfreq and cooling device support
  - drm/lima: Various improvements wrt. task handling
  - drm/panel: nt39016: Support multiple modes and 50Hz
  - drm/panel: Support Leadtek LTK050H3146W
  - drm/rockchip: Add support for afbc
  - drm/virtio: Various cleanups
  - drm/hisilicon/hibmc: Enforce 128-byte stride alignment
  - drm/qxl: Fix notify port address of cursor ring buffer
  - drm/sun4i: Improvements to format handling
  - drm/bridge: dw-hdmi: Various improvements

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414090738.GA16827@linux-uq9g

1 files changed, 75 insertions, 19 deletions

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index da7b0b0c1090..758bf74e1cab 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_managed.h>
 #include <drm/drm_modeset_helper_vtables.h>
 #include <drm/drm_print.h>
 #include <drm/drm_vblank.h>
@@ -40,6 +41,69 @@
 /**
  * DOC: vblank handling
  *
+ * From the computer's perspective, every time the monitor displays
+ * a new frame the scanout engine has "scanned out" the display image
+ * from top to bottom, one row of pixels at a time. The current row
+ * of pixels is referred to as the current scanline.
+ *
+ * In addition to the display's visible area, there's usually a couple of
+ * extra scanlines which aren't actually displayed on the screen.
+ * These extra scanlines don't contain image data and are occasionally used
+ * for features like audio and infoframes. The region made up of these
+ * scanlines is referred to as the vertical blanking region, or vblank for
+ * short.
+ *
+ * For historical reference, the vertical blanking period was designed to
+ * give the electron gun (on CRTs) enough time to move back to the top of
+ * the screen to start scanning out the next frame. Similar for horizontal
+ * blanking periods. They were designed to give the electron gun enough
+ * time to move back to the other side of the screen to start scanning the
+ * next scanline.
+ *
+ * ::
+ *
+ *
+ *    physical →   ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽
+ *    top of      |                                        |
+ *    display     |                                        |
+ *                |               New frame                |
+ *                |                                        |
+ *                |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓|
+ *                |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| ← Scanline,
+ *                |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓|   updates the
+ *                |                                        |   frame as it
+ *                |                                        |   travels down
+ *                |                                        |   ("sacn out")
+ *                |               Old frame                |
+ *                |                                        |
+ *                |                                        |
+ *                |                                        |
+ *                |                                        |   physical
+ *                |                                        |   bottom of
+ *    vertical    |⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽| ← display
+ *    blanking    ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
+ *    region   →  ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
+ *                ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
+ *    start of →   ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽
+ *    new frame
+ *
+ * "Physical top of display" is the reference point for the high-precision/
+ * corrected timestamp.
+ *
+ * On a lot of display hardware, programming needs to take effect during the
+ * vertical blanking period so that settings like gamma, the image buffer
+ * buffer to be scanned out, etc. can safely be changed without showing
+ * any visual artifacts on the screen. In some unforgiving hardware, some of
+ * this programming has to both start and end in the same vblank. To help
+ * with the timing of the hardware programming, an interrupt is usually
+ * available to notify the driver when it can start the updating of registers.
+ * The interrupt is in this context named the vblank interrupt.
+ *
+ * The vblank interrupt may be fired at different points depending on the
+ * hardware. Some hardware implementations will fire the interrupt when the
+ * new frame start, other implementations will fire the interrupt at different
+ * points in time.
+ *
  * Vertical blanking plays a major role in graphics rendering. To achieve
  * tear-free display, users must synchronize page flips and/or rendering to
  * vertical blanking. The DRM API offers ioctls to perform page flips
@@ -425,14 +489,10 @@ static void vblank_disable_fn(struct timer_list *t)
 	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 }
 
-void drm_vblank_cleanup(struct drm_device *dev)
+static void drm_vblank_init_release(struct drm_device *dev, void *ptr)
 {
 	unsigned int pipe;
 
-	/* Bail if the driver didn't call drm_vblank_init() */
-	if (dev->num_crtcs == 0)
-		return;
-
 	for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
 		struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 
@@ -441,10 +501,6 @@ void drm_vblank_cleanup(struct drm_device *dev)
 
 		del_timer_sync(&vblank->disable_timer);
 	}
-
-	kfree(dev->vblank);
-
-	dev->num_crtcs = 0;
 }
 
 /**
@@ -453,25 +509,29 @@ void drm_vblank_cleanup(struct drm_device *dev)
  * @num_crtcs: number of CRTCs supported by @dev
  *
  * This function initializes vblank support for @num_crtcs display pipelines.
- * Cleanup is handled by the DRM core, or through calling drm_dev_fini() for
- * drivers with a &drm_driver.release callback.
+ * Cleanup is handled automatically through a cleanup function added with
+ * drmm_add_action().
  *
  * Returns:
  * Zero on success or a negative error code on failure.
  */
 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
 {
-	int ret = -ENOMEM;
+	int ret;
 	unsigned int i;
 
 	spin_lock_init(&dev->vbl_lock);
 	spin_lock_init(&dev->vblank_time_lock);
 
+	dev->vblank = drmm_kcalloc(dev, num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
+	if (!dev->vblank)
+		return -ENOMEM;
+
 	dev->num_crtcs = num_crtcs;
 
-	dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
-	if (!dev->vblank)
-		goto err;
+	ret = drmm_add_action(dev, drm_vblank_init_release, NULL);
+	if (ret)
+		return ret;
 
 	for (i = 0; i < num_crtcs; i++) {
 		struct drm_vblank_crtc *vblank = &dev->vblank[i];
@@ -486,10 +546,6 @@ int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
 	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
 
 	return 0;
-
-err:
-	dev->num_crtcs = 0;
-	return ret;
 }
 EXPORT_SYMBOL(drm_vblank_init);