From babc250e278eac7b0e671bdaedf833759b43bb78 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 1 Apr 2019 17:46:57 +0200 Subject: udlfb: introduce a rendering mutex Rendering calls may be done simultaneously from the workqueue, dlfb_ops_write, dlfb_ops_ioctl, dlfb_ops_set_par and dlfb_dpy_deferred_io. The code is robust enough so that it won't crash on concurrent rendering. However, concurrent rendering may cause display corruption if the same pixel is simultaneously being rendered. In order to avoid this corruption, this patch adds a mutex around the rendering calls. Signed-off-by: Mikulas Patocka Cc: Bernie Thompson Cc: Ladislav Michl Cc: [b.zolnierkie: replace "dlfb:" with "uldfb:" in the patch summary] Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/video/fbdev/udlfb.c | 41 ++++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 11 deletions(-) (limited to 'drivers/video/fbdev') diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c index ce30fa710244..5a0d6fb02bbc 100644 --- a/drivers/video/fbdev/udlfb.c +++ b/drivers/video/fbdev/udlfb.c @@ -596,7 +596,7 @@ static int dlfb_render_hline(struct dlfb_data *dlfb, struct urb **urb_ptr, static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y, int width, int height) { - int i; + int i, ret; char *cmd; cycles_t start_cycles, end_cycles; int bytes_sent = 0; @@ -606,21 +606,29 @@ static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y, int width, i start_cycles = get_cycles(); + mutex_lock(&dlfb->render_mutex); + aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long)); width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long)); x = aligned_x; if ((width <= 0) || (x + width > dlfb->info->var.xres) || - (y + height > dlfb->info->var.yres)) - return -EINVAL; + (y + height > dlfb->info->var.yres)) { + ret = -EINVAL; + goto unlock_ret; + } - if (!atomic_read(&dlfb->usb_active)) - return 0; + if (!atomic_read(&dlfb->usb_active)) { + ret = 0; + goto unlock_ret; + } urb = dlfb_get_urb(dlfb); - if (!urb) - return 0; + if (!urb) { + ret = 0; + goto unlock_ret; + } cmd = urb->transfer_buffer; for (i = y; i < y + height ; i++) { @@ -654,7 +662,11 @@ error: >> 10)), /* Kcycles */ &dlfb->cpu_kcycles_used); - return 0; + ret = 0; + +unlock_ret: + mutex_unlock(&dlfb->render_mutex); + return ret; } static void dlfb_init_damage(struct dlfb_data *dlfb) @@ -782,17 +794,19 @@ static void dlfb_dpy_deferred_io(struct fb_info *info, int bytes_identical = 0; int bytes_rendered = 0; + mutex_lock(&dlfb->render_mutex); + if (!fb_defio) - return; + goto unlock_ret; if (!atomic_read(&dlfb->usb_active)) - return; + goto unlock_ret; start_cycles = get_cycles(); urb = dlfb_get_urb(dlfb); if (!urb) - return; + goto unlock_ret; cmd = urb->transfer_buffer; @@ -825,6 +839,8 @@ error: atomic_add(((unsigned int) ((end_cycles - start_cycles) >> 10)), /* Kcycles */ &dlfb->cpu_kcycles_used); +unlock_ret: + mutex_unlock(&dlfb->render_mutex); } static int dlfb_get_edid(struct dlfb_data *dlfb, char *edid, int len) @@ -986,6 +1002,8 @@ static void dlfb_ops_destroy(struct fb_info *info) cancel_work_sync(&dlfb->damage_work); + mutex_destroy(&dlfb->render_mutex); + if (info->cmap.len != 0) fb_dealloc_cmap(&info->cmap); if (info->monspecs.modedb) @@ -1682,6 +1700,7 @@ static int dlfb_usb_probe(struct usb_interface *intf, dlfb->ops = dlfb_ops; info->fbops = &dlfb->ops; + mutex_init(&dlfb->render_mutex); dlfb_init_damage(dlfb); spin_lock_init(&dlfb->damage_lock); INIT_WORK(&dlfb->damage_work, dlfb_damage_work); -- cgit v1.2.3