Re: [RFC v2 1/8] drm/fb-helper: Add fb_deferred_io support

On Fri, Apr 08, 2016 at 07:05:03PM +0200, Noralf Trønnes wrote:

This adds deferred io support if CONFIG_FB_DEFERRED_IO is enabled. Accumulated fbdev framebuffer changes are signaled using the callback (struct drm_framebuffer_funcs *)->dirty()

The drm_fb_helper_sys_*() functions will accumulate changes and schedule fb_info.deferred_work _if_ fb_info.fbdefio is set. This worker is used by the deferred io mmap code to signal that it has been collecting page faults. The page faults and/or other changes are then merged into a drm_clip_rect and passed to the framebuffer dirty() function.

The driver is responsible for setting up the fb_info.fbdefio structure and calling fb_deferred_io_init() using the provided callback: (struct fb_info *)->fbdefio->deferred_io = drm_fb_helper_deferred_io;

Signed-off-by: Noralf Trønnes noralf@tronnes.org

For this one it'd be awesome to throw patches for qxl/udl on top to remove their own hand-rolled implementations. Just to maximize the testing coverage of this new code. Should be doable to set up a qxl virtual machine quickly, but even without that we should be able to pull it in (since it's mostly just about removing code from these two drivers). -Daniel

---

drivers/gpu/drm/drm_fb_helper.c | 189 +++++++++++++++++++++++++++++++++++++++- include/drm/drm_fb_helper.h | 15 ++++ 2 files changed, 203 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 1e103c4..30f3dfd 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -48,6 +48,100 @@ MODULE_PARM_DESC(fbdev_emulation,

static LIST_HEAD(kernel_fb_helper_list);

+/*

• • Where should I put these drm_clip_rect functions?
• */

+/**

• • drm_clip_rect_reset - Reset clip
• • @clip: clip rectangle
• • Sets clip to {0,0,0,0}.
• */

+static inline void drm_clip_rect_reset(struct drm_clip_rect *clip) +{

• clip->x1 = 0;
• clip->x2 = 0;
• clip->y1 = 0;
• clip->y2 = 0;

+}

+/**

• • drm_clip_rect_is_empty - Is clip empty?
• • @clip: clip rectangle
• • Returns true if clip is {0,0,0,0}.
• */

+static inline bool drm_clip_rect_is_empty(struct drm_clip_rect *clip) +{

• return (!clip->x1 && !clip->x2 && !clip->y1 && !clip->y2);

+}

+/**

• • drm_clip_rect_sanetize - Make sure clip rectangle has sane values
• • @clip: clip rectangle
• • @width: maximum width of rectangle
• • @height: maximum height of rectangle
• • Makes sure the clip doesn't exceed the specified width and height and that
• • x1 <= x2 and y1 <= y2.
• */

+void drm_clip_rect_sanetize(struct drm_clip_rect *clip, u32 width, u32 height) +{

• if (clip->x1 > clip->x2)

• swap(clip->x1, clip->x2);
  

• if (clip->y1 > clip->y2)

• swap(clip->y1, clip->y2);
  

• clip->x1 = min_t(u32, clip->x1, width - 1);
• clip->x2 = min_t(u32, clip->x2, width - 1);
• clip->y1 = min_t(u32, clip->y1, height - 1);
• clip->y2 = min_t(u32, clip->y2, height - 1);

+} +EXPORT_SYMBOL(drm_clip_rect_sanetize);

+/**

• • drm_clip_rect_merge - Merge clip rectangles
• • @dst: destination clip rectangle
• • @src: source clip rectangle(s), can be NULL
• • @num_clips: number of source clip rectangles
• • @width: width of rectangle if @src is NULL
• • @height: height of rectangle if @src is NULL
• • The dirtyfb ioctl allows for a NULL clip to be passed in,
• • so if @src is NULL, width and height is used to set a full clip.
• • @dst takes part in the merge unless it is empty {0,0,0,0}.
• */

+void drm_clip_rect_merge(struct drm_clip_rect *dst,

• 	 struct drm_clip_rect *src, unsigned num_clips,
  

• 	 unsigned flags, u32 width, u32 height)
  

+{

• int i;
• if (!src || !num_clips) {

• dst->x1 = 0;
  

• dst->x2 = width - 1;
  

• dst->y1 = 0;
  

• dst->y2 = height - 1;
  

• return;
  

• }
• if (drm_clip_rect_is_empty(dst)) {

• dst->x1 = ~0;
  

• dst->y1 = ~0;
  

• }
• for (i = 0; i < num_clips; i++) {

• if (flags & DRM_MODE_FB_DIRTY_ANNOTATE_COPY)
  

• 	i++;
  

• dst->x1 = min(dst->x1, src[i].x1);
  

• dst->x2 = max(dst->x2, src[i].x2);
  

• dst->y1 = min(dst->y1, src[i].y1);
  

• dst->y2 = max(dst->y2, src[i].y2);
  

• }

+} +EXPORT_SYMBOL(drm_clip_rect_merge);

/**

• DOC: fbdev helpers

@@ -410,6 +504,13 @@ static int restore_fbdev_mode(struct drm_fb_helper *fb_helper)

drm_warn_on_modeset_not_all_locked(dev);

+#ifdef CONFIG_FB_DEFERRED_IO

• spin_lock(&fb_helper->dirty_lock);
• drm_clip_rect_merge(&fb_helper->dirty_clip, NULL, 0, 0,

• 	    fb_helper->fbdev->var.xres,
  

• 	    fb_helper->fbdev->var.yres);
  

• spin_unlock(&fb_helper->dirty_lock);

+#endif if (fb_helper->atomic) return restore_fbdev_mode_atomic(fb_helper);

@@ -654,6 +755,9 @@ void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper, const struct drm_fb_helper_funcs *funcs) { INIT_LIST_HEAD(&helper->kernel_fb_list); +#ifdef CONFIG_FB_DEFERRED_IO

• spin_lock_init(&helper->dirty_lock);

+#endif helper->funcs = funcs; helper->dev = dev; } @@ -838,6 +942,76 @@ void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper) } EXPORT_SYMBOL(drm_fb_helper_unlink_fbi);

+#ifdef CONFIG_FB_DEFERRED_IO +void drm_fb_helper_deferred_io(struct fb_info *info,

• 	       struct list_head *pagelist)
  

+{

• struct drm_fb_helper *helper = info->par;
• unsigned long start, end, min, max;
• struct drm_clip_rect clip;
• struct page *page;
• if (!helper->fb->funcs->dirty)

• return;
  

• spin_lock(&helper->dirty_lock);
• clip = helper->dirty_clip;
• drm_clip_rect_reset(&helper->dirty_clip);
• spin_unlock(&helper->dirty_lock);
• min = ULONG_MAX;
• max = 0;
• list_for_each_entry(page, pagelist, lru) {

• start = page->index << PAGE_SHIFT;
  

• end = start + PAGE_SIZE - 1;
  

• min = min(min, start);
  

• max = max(max, end);
  

• }
• if (min < max) {

• clip.x1 = 0;
  

• clip.x2 = info->var.xres - 1;
  

• clip.y1 = min / info->fix.line_length;
  

• clip.y2 = min_t(u32, max / info->fix.line_length,
  

• 		    info->var.yres - 1);
  

• } else if (drm_clip_rect_is_empty(&clip)) {

• clip.x1 = 0;
  

• clip.x2 = info->var.xres - 1;
  

• clip.y1 = 0;
  

• clip.y2 = info->var.yres - 1;
  

• }
• helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip, 1);

+} +EXPORT_SYMBOL(drm_fb_helper_deferred_io);

+static void drm_fb_helper_sys_deferred(struct fb_info *info, u32 x, u32 y,

• 		       u32 width, u32 height)
  

+{

• struct drm_fb_helper *helper = info->par;
• struct drm_clip_rect clip;
• if (!info->fbdefio)

• return;
  

• clip.x1 = x;
• clip.x2 = x + width - 1;
• clip.y1 = y;
• clip.y2 = y + height - 1;
• spin_lock(&helper->dirty_lock);
• drm_clip_rect_merge(&helper->dirty_clip, &clip, 1, 0, 0, 0);
• spin_unlock(&helper->dirty_lock);
• schedule_delayed_work(&info->deferred_work, info->fbdefio->delay);

+} +#else +static inline void drm_fb_helper_sys_deferred(struct fb_info *info, u32 x, u32 y,

• 			      u32 width, u32 height)
  

+{ +} +#endif

/**

• drm_fb_helper_sys_read - wrapper around fb_sys_read
• @info: fb_info struct pointer

@@ -866,7 +1040,14 @@ EXPORT_SYMBOL(drm_fb_helper_sys_read); ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char __user *buf, size_t count, loff_t *ppos) {

• return fb_sys_write(info, buf, count, ppos);

• ssize_t ret;
• ret = fb_sys_write(info, buf, count, ppos);
• if (ret > 0)

• drm_fb_helper_sys_deferred(info, 0, 0,
  

• 			   info->var.xres, info->var.yres);
  

• return ret;

} EXPORT_SYMBOL(drm_fb_helper_sys_write);

@@ -881,6 +1062,8 @@ void drm_fb_helper_sys_fillrect(struct fb_info *info, const struct fb_fillrect *rect) { sys_fillrect(info, rect);

• drm_fb_helper_sys_deferred(info, rect->dx, rect->dy,

• 		   rect->width, rect->height);
  

} EXPORT_SYMBOL(drm_fb_helper_sys_fillrect);

@@ -895,6 +1078,8 @@ void drm_fb_helper_sys_copyarea(struct fb_info *info, const struct fb_copyarea *area) { sys_copyarea(info, area);

• drm_fb_helper_sys_deferred(info, area->dx, area->dy,

• 		   area->width, area->height);
  

} EXPORT_SYMBOL(drm_fb_helper_sys_copyarea);

@@ -909,6 +1094,8 @@ void drm_fb_helper_sys_imageblit(struct fb_info *info, const struct fb_image *image) { sys_imageblit(info, image);

• drm_fb_helper_sys_deferred(info, image->dx, image->dy,

• 		   image->width, image->height);
  

} EXPORT_SYMBOL(drm_fb_helper_sys_imageblit);

diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index d8a40df..1daadc7 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -172,6 +172,9 @@ struct drm_fb_helper_connector {

• @funcs: driver callbacks for fb helper
• @fbdev: emulated fbdev device info struct
• @pseudo_palette: fake palette of 16 colors

• • @dirty_clip: clip rectangle used with deferred_io to accumulate damage to

• •          the screen buffer
    

• • @dirty_lock: spinlock protecting @dirty_clip
  • This is the main structure used by the fbdev helpers. Drivers supporting
  • fbdev emulation should embedded this into their overall driver structure.

@@ -189,6 +192,10 @@ struct drm_fb_helper { const struct drm_fb_helper_funcs *funcs; struct fb_info *fbdev; u32 pseudo_palette[17]; +#ifdef CONFIG_FB_DEFERRED_IO

• struct drm_clip_rect dirty_clip;
• spinlock_t dirty_lock;

+#endif

/** * @kernel_fb_list: @@ -244,6 +251,9 @@ void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,

void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper);

+void drm_fb_helper_deferred_io(struct fb_info *info,

• 	       struct list_head *pagelist);
  

ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf, size_t count, loff_t *ppos); ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char __user *buf, @@ -362,6 +372,11 @@ static inline void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper) { }

+static inline void drm_fb_helper_deferred_io(struct fb_info *info,

• 			     struct list_head *pagelist)
  

+{ +}

static inline ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf, size_t count, loff_t *ppos) -- 2.2.2

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