From 958f44255058338f4b370d8e4100e1e7d72db0cc Mon Sep 17 00:00:00 2001 From: Dan Moulding Date: Tue, 10 Aug 2021 13:59:06 -0600 Subject: [PATCH 1/2] drm: ttm: Don't bail from ttm_global_init if debugfs_create_dir fails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In 69de4421bb4c ("drm/ttm: Initialize debugfs from ttm_global_init()"), ttm_global_init was changed so that if creation of the debugfs global root directory fails, ttm_global_init will bail out early and return an error, leading to initialization failure of DRM drivers. However, not every system will be using debugfs. On such a system, debugfs directory creation can be expected to fail, but DRM drivers must still be usable. This changes it so that if creation of TTM's debugfs root directory fails, then no biggie: keep calm and carry on. Fixes: 69de4421bb4c ("drm/ttm: Initialize debugfs from ttm_global_init()") Signed-off-by: Dan Moulding Tested-by: Huacai Chen Reviewed-by: Huang Rui Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20210810195906.22220-2-dmoulding@me.com Signed-off-by: Christian König --- drivers/gpu/drm/ttm/ttm_device.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c index 74e3b460132b..2df59b3c2ea1 100644 --- a/drivers/gpu/drm/ttm/ttm_device.c +++ b/drivers/gpu/drm/ttm/ttm_device.c @@ -78,9 +78,7 @@ static int ttm_global_init(void) ttm_debugfs_root = debugfs_create_dir("ttm", NULL); if (IS_ERR(ttm_debugfs_root)) { - ret = PTR_ERR(ttm_debugfs_root); ttm_debugfs_root = NULL; - goto out; } /* Limit the number of pages in the pool to about 50% of the total From fa0b1ef5f7a694f48e00804a391245f3471aa155 Mon Sep 17 00:00:00 2001 From: Mark Yacoub Date: Thu, 12 Aug 2021 15:49:17 -0400 Subject: [PATCH 2/2] drm: Copy drm_wait_vblank to user before returning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [Why] Userspace should get back a copy of drm_wait_vblank that's been modified even when drm_wait_vblank_ioctl returns a failure. Rationale: drm_wait_vblank_ioctl modifies the request and expects the user to read it back. When the type is RELATIVE, it modifies it to ABSOLUTE and updates the sequence to become current_vblank_count + sequence (which was RELATIVE), but now it became ABSOLUTE. drmWaitVBlank (in libdrm) expects this to be the case as it modifies the request to be Absolute so it expects the sequence to would have been updated. The change is in compat_drm_wait_vblank, which is called by drm_compat_ioctl. This change of copying the data back regardless of the return number makes it en par with drm_ioctl, which always copies the data before returning. [How] Return from the function after everything has been copied to user. Fixes IGT:kms_flip::modeset-vs-vblank-race-interruptible Tested on ChromeOS Trogdor(msm) Reviewed-by: Michel Dänzer Signed-off-by: Mark Yacoub Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20210812194917.1703356-1-markyacoub@chromium.org --- drivers/gpu/drm/drm_ioc32.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c index d29907955ff7..5d82891c3222 100644 --- a/drivers/gpu/drm/drm_ioc32.c +++ b/drivers/gpu/drm/drm_ioc32.c @@ -855,8 +855,6 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd, req.request.sequence = req32.request.sequence; req.request.signal = req32.request.signal; err = drm_ioctl_kernel(file, drm_wait_vblank_ioctl, &req, DRM_UNLOCKED); - if (err) - return err; req32.reply.type = req.reply.type; req32.reply.sequence = req.reply.sequence; @@ -865,7 +863,7 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd, if (copy_to_user(argp, &req32, sizeof(req32))) return -EFAULT; - return 0; + return err; } #if defined(CONFIG_X86)