From eaa434defaca1781fb2932c685289b610aeb8b4b Mon Sep 17 00:00:00 2001 From: Noralf Trønnes Date: Thu, 28 Apr 2016 17:18:33 +0200 Subject: drm/fb-helper: Add fb_deferred_io support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds deferred io support to drm_fb_helper. The fbdev framebuffer changes are flushed using the callback (struct drm_framebuffer *)->funcs->dirty() by a dedicated worker ensuring that it always runs in process context. For those wondering why we need to be able to handle atomic calling contexts: Both panic paths and cursor code and fbcon blanking can run from atomic. See commit bcb39af4486be07e896fc374a2336bad3104ae0a Author: Dave Airlie Date: Thu Feb 7 11:19:15 2013 +1000 drm/udl: make usage as a console safer for where this was originally discovered. Signed-off-by: Noralf Trønnes Reviewed-by: Daniel Vetter [danvet: Augment commit message with why we need to handle atomic contexts.] Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1461856717-6476-4-git-send-email-noralf@tronnes.org --- drivers/gpu/drm/Kconfig | 1 + drivers/gpu/drm/drm_fb_helper.c | 103 +++++++++++++++++++++++++++++++++++++++- include/drm/drm_fb_helper.h | 15 ++++++ 3 files changed, 118 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index f2a74d0b68ae..414c79bf63a7 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -52,6 +52,7 @@ config DRM_KMS_FB_HELPER select FB_CFB_FILLRECT select FB_CFB_COPYAREA select FB_CFB_IMAGEBLIT + select FB_DEFERRED_IO help FBDEV helpers for KMS drivers. diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 855108e6e1bd..62f849f2fe44 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -84,6 +84,15 @@ static LIST_HEAD(kernel_fb_helper_list); * and set up an initial configuration using the detected hardware, drivers * should call drm_fb_helper_single_add_all_connectors() followed by * drm_fb_helper_initial_config(). + * + * If CONFIG_FB_DEFERRED_IO is enabled and &drm_framebuffer_funcs ->dirty is + * set, the drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} + * functions will accumulate changes and schedule &fb_helper .dirty_work to run + * right away. This worker then calls the dirty() function ensuring that it + * will always run in process context since the fb_*() function could be + * running in atomic context. If drm_fb_helper_deferred_io() is used as the + * deferred_io callback it will also schedule dirty_work with the damage + * collected from the mmap page writes. */ /** @@ -637,6 +646,23 @@ static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper) kfree(helper->crtc_info); } +static void drm_fb_helper_dirty_work(struct work_struct *work) +{ + struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper, + dirty_work); + struct drm_clip_rect *clip = &helper->dirty_clip; + struct drm_clip_rect clip_copy; + unsigned long flags; + + spin_lock_irqsave(&helper->dirty_lock, flags); + clip_copy = *clip; + clip->x1 = clip->y1 = ~0; + clip->x2 = clip->y2 = 0; + spin_unlock_irqrestore(&helper->dirty_lock, flags); + + helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip_copy, 1); +} + /** * drm_fb_helper_prepare - setup a drm_fb_helper structure * @dev: DRM device @@ -650,6 +676,9 @@ 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); + spin_lock_init(&helper->dirty_lock); + INIT_WORK(&helper->dirty_work, drm_fb_helper_dirty_work); + helper->dirty_clip.x1 = helper->dirty_clip.y1 = ~0; helper->funcs = funcs; helper->dev = dev; } @@ -834,6 +863,59 @@ void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper) } EXPORT_SYMBOL(drm_fb_helper_unlink_fbi); +static void drm_fb_helper_dirty(struct fb_info *info, u32 x, u32 y, + u32 width, u32 height) +{ + struct drm_fb_helper *helper = info->par; + struct drm_clip_rect *clip = &helper->dirty_clip; + unsigned long flags; + + if (!helper->fb->funcs->dirty) + return; + + spin_lock_irqsave(&helper->dirty_lock, flags); + clip->x1 = min_t(u32, clip->x1, x); + clip->y1 = min_t(u32, clip->y1, y); + clip->x2 = max_t(u32, clip->x2, x + width); + clip->y2 = max_t(u32, clip->y2, y + height); + spin_unlock_irqrestore(&helper->dirty_lock, flags); + + schedule_work(&helper->dirty_work); +} + +/** + * drm_fb_helper_deferred_io() - fbdev deferred_io callback function + * @info: fb_info struct pointer + * @pagelist: list of dirty mmap framebuffer pages + * + * This function is used as the &fb_deferred_io ->deferred_io + * callback function for flushing the fbdev mmap writes. + */ +void drm_fb_helper_deferred_io(struct fb_info *info, + struct list_head *pagelist) +{ + unsigned long start, end, min, max; + struct page *page; + u32 y1, y2; + + 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) { + y1 = min / info->fix.line_length; + y2 = min_t(u32, DIV_ROUND_UP(max, info->fix.line_length), + info->var.yres); + drm_fb_helper_dirty(info, 0, y1, info->var.xres, y2 - y1); + } +} +EXPORT_SYMBOL(drm_fb_helper_deferred_io); + /** * drm_fb_helper_sys_read - wrapper around fb_sys_read * @info: fb_info struct pointer @@ -862,7 +944,14 @@ 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_dirty(info, 0, 0, info->var.xres, + info->var.yres); + + return ret; } EXPORT_SYMBOL(drm_fb_helper_sys_write); @@ -877,6 +966,8 @@ void drm_fb_helper_sys_fillrect(struct fb_info *info, const struct fb_fillrect *rect) { sys_fillrect(info, rect); + drm_fb_helper_dirty(info, rect->dx, rect->dy, + rect->width, rect->height); } EXPORT_SYMBOL(drm_fb_helper_sys_fillrect); @@ -891,6 +982,8 @@ void drm_fb_helper_sys_copyarea(struct fb_info *info, const struct fb_copyarea *area) { sys_copyarea(info, area); + drm_fb_helper_dirty(info, area->dx, area->dy, + area->width, area->height); } EXPORT_SYMBOL(drm_fb_helper_sys_copyarea); @@ -905,6 +998,8 @@ void drm_fb_helper_sys_imageblit(struct fb_info *info, const struct fb_image *image) { sys_imageblit(info, image); + drm_fb_helper_dirty(info, image->dx, image->dy, + image->width, image->height); } EXPORT_SYMBOL(drm_fb_helper_sys_imageblit); @@ -919,6 +1014,8 @@ void drm_fb_helper_cfb_fillrect(struct fb_info *info, const struct fb_fillrect *rect) { cfb_fillrect(info, rect); + drm_fb_helper_dirty(info, rect->dx, rect->dy, + rect->width, rect->height); } EXPORT_SYMBOL(drm_fb_helper_cfb_fillrect); @@ -933,6 +1030,8 @@ void drm_fb_helper_cfb_copyarea(struct fb_info *info, const struct fb_copyarea *area) { cfb_copyarea(info, area); + drm_fb_helper_dirty(info, area->dx, area->dy, + area->width, area->height); } EXPORT_SYMBOL(drm_fb_helper_cfb_copyarea); @@ -947,6 +1046,8 @@ void drm_fb_helper_cfb_imageblit(struct fb_info *info, const struct fb_image *image) { cfb_imageblit(info, image); + drm_fb_helper_dirty(info, image->dx, image->dy, + image->width, image->height); } EXPORT_SYMBOL(drm_fb_helper_cfb_imageblit); diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index 062723bdcabe..5b4aa35026a3 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -172,6 +172,10 @@ 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 + * @dirty_work: worker used to flush the framebuffer * * This is the main structure used by the fbdev helpers. Drivers supporting * fbdev emulation should embedded this into their overall driver structure. @@ -189,6 +193,9 @@ struct drm_fb_helper { const struct drm_fb_helper_funcs *funcs; struct fb_info *fbdev; u32 pseudo_palette[17]; + struct drm_clip_rect dirty_clip; + spinlock_t dirty_lock; + struct work_struct dirty_work; /** * @kernel_fb_list: @@ -245,6 +252,9 @@ 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, @@ -368,6 +378,11 @@ 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) -- cgit