Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754123AbcDYJKE (ORCPT ); Mon, 25 Apr 2016 05:10:04 -0400 Received: from mail-wm0-f49.google.com ([74.125.82.49]:38201 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750793AbcDYJKB (ORCPT ); Mon, 25 Apr 2016 05:10:01 -0400 Date: Mon, 25 Apr 2016 11:09:57 +0200 From: Daniel Vetter To: Noralf =?iso-8859-1?Q?Tr=F8nnes?= Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, daniel@ffwll.ch, laurent.pinchart@ideasonboard.com, tomi.valkeinen@ti.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/8] drm/fb-helper: Add fb_deferred_io support Message-ID: <20160425090957.GQ2510@phenom.ffwll.local> Mail-Followup-To: Noralf =?iso-8859-1?Q?Tr=F8nnes?= , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, laurent.pinchart@ideasonboard.com, tomi.valkeinen@ti.com, linux-kernel@vger.kernel.org References: <1461530942-22485-1-git-send-email-noralf@tronnes.org> <1461530942-22485-5-git-send-email-noralf@tronnes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1461530942-22485-5-git-send-email-noralf@tronnes.org> X-Operating-System: Linux phenom 4.4.0-1-amd64 User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10807 Lines: 319 On Sun, Apr 24, 2016 at 10:48:58PM +0200, Noralf Tr?nnes wrote: > This adds deferred io support if CONFIG_FB_DEFERRED_IO is enabled. > 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. > > Signed-off-by: Noralf Tr?nnes > --- > > Changes since v1: > - Use a dedicated worker to run the framebuffer flushing like qxl does > - Add parameter descriptions to drm_fb_helper_deferred_io > > drivers/gpu/drm/drm_fb_helper.c | 127 +++++++++++++++++++++++++++++++++++++++- > include/drm/drm_fb_helper.h | 17 ++++++ > 2 files changed, 143 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c > index 855108e..46ee6f8 100644 > --- a/drivers/gpu/drm/drm_fb_helper.c > +++ b/drivers/gpu/drm/drm_fb_helper.c > @@ -40,6 +40,7 @@ > #include > #include > #include > +#include > > static bool drm_fbdev_emulation = true; > module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600); > @@ -48,6 +49,10 @@ MODULE_PARM_DESC(fbdev_emulation, > > static LIST_HEAD(kernel_fb_helper_list); > > +static void drm_fb_helper_dirty_init(struct drm_fb_helper *helper); > +static void drm_fb_helper_dirty(struct fb_info *info, u32 x, u32 y, > + u32 width, u32 height); > + > /** > * DOC: fbdev helpers > * > @@ -84,6 +89,16 @@ 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 > + * (struct drm_framebuffer *)->funcs->dirty is set, the > + * drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} functions > + * will accumulate changes and schedule (struct 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. One thing to consider (and personally I don't care either way) is whether we shouldn't just select CONFIG_FB_DEFERRED_IO if the fbdev helpers are enabled. Pushing that out to drivers is imo a bit fragile. But like I said I'm ok with either way. > */ > > /** > @@ -401,11 +416,14 @@ backoff: > static int restore_fbdev_mode(struct drm_fb_helper *fb_helper) > { > struct drm_device *dev = fb_helper->dev; > + struct fb_info *info = fb_helper->fbdev; > struct drm_plane *plane; > int i; > > drm_warn_on_modeset_not_all_locked(dev); > > + drm_fb_helper_dirty(info, 0, 0, info->var.xres, info->var.yres); Why is this needed? If you do a modeset (or pageflip or whatever) drivers are supposed to re-upload the entire screen. We've talked about adding a dirty rectangle to atomic to allow userspace to optimize this, but there should _never_ be a need to do a dirtyfb call around a modeset. Probably just a driver bug in your panel drm drivers? With the above line removed: Reviewed-by: Daniel Vetter > + > if (fb_helper->atomic) > return restore_fbdev_mode_atomic(fb_helper); > > @@ -650,6 +668,7 @@ 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); > + drm_fb_helper_dirty_init(helper); > helper->funcs = funcs; > helper->dev = dev; > } > @@ -834,6 +853,93 @@ void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper) > } > EXPORT_SYMBOL(drm_fb_helper_unlink_fbi); > > +#ifdef CONFIG_FB_DEFERRED_IO > +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; > + unsigned long flags; > + > + spin_lock_irqsave(&helper->dirty_lock, flags); > + clip = helper->dirty_clip; > + drm_clip_rect_reset(&helper->dirty_clip); > + spin_unlock_irqrestore(&helper->dirty_lock, flags); > + > + helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip, 1); > +} > + > +static void drm_fb_helper_dirty_init(struct drm_fb_helper *helper) > +{ > + spin_lock_init(&helper->dirty_lock); > + INIT_WORK(&helper->dirty_work, drm_fb_helper_dirty_work); > +} > + > +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; > + unsigned long flags; > + > + if (!helper->fb->funcs->dirty) > + return; > + > + clip.x1 = x; > + clip.x2 = x + width; > + clip.y1 = y; > + clip.y2 = y + height; > + > + spin_lock_irqsave(&helper->dirty_lock, flags); > + drm_clip_rect_merge(&helper->dirty_clip, &clip, 1, 0, 0, 0); > + 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 (struct 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, 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); > + > +#else > +static void drm_fb_helper_dirty_init(struct drm_fb_helper *helper) > +{ > +} > + > +static void drm_fb_helper_dirty(struct fb_info *info, u32 x, u32 y, > + u32 width, u32 height) > +{ > +} > +#endif /* CONFIG_FB_DEFERRED_IO */ > + > /** > * drm_fb_helper_sys_read - wrapper around fb_sys_read > * @info: fb_info struct pointer > @@ -862,7 +968,14 @@ 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 +990,8 @@ 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 +1006,8 @@ 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 +1022,8 @@ 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 +1038,8 @@ 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 +1054,8 @@ 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 +1070,8 @@ 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 062723b..dde825c 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 +193,11 @@ 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; > + struct work_struct dirty_work; > +#endif > > /** > * @kernel_fb_list: > @@ -245,6 +254,9 @@ 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 +380,11 @@ 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 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch