From b77f0765fdfb3a115e40effd890acb4674dc0989 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Tue, 29 Apr 2014 11:44:32 +0200 Subject: drm: Try to acquire modeset lock on panic or sysrq Commit 62ff94a54921 "drm/crtc-helper: remove LOCKING from kerneldoc" causes drm_helper_crtc_in_use() and drm_helper_encoder_in_use() to complain loudly during a kernel panic or sysrq processing. This is caused by nobody acquiring the modeset lock in these code paths. This patch fixes this by trying to acquire the modeset lock for each FB helper that's forced to kernel mode. If the lock can't be acquired, it's likely that somebody else is performing a modeset. However, doing another modeset concurrently might make things even worse, so the safe option is to simply bail out in that case. Reviewed-by: Daniel Vetter Reviewed-by: David Herrmann Signed-off-by: Thierry Reding Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_fb_helper.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/drm_fb_helper.c') diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 04d3fd3658f3..158d8e51db3d 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -326,12 +326,21 @@ static bool drm_fb_helper_force_kernel_mode(void) return false; list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) { - if (helper->dev->switch_power_state == DRM_SWITCH_POWER_OFF) + struct drm_device *dev = helper->dev; + + if (dev->switch_power_state == DRM_SWITCH_POWER_OFF) + continue; + + if (!mutex_trylock(&dev->mode_config.mutex)) { + error = true; continue; + } ret = drm_fb_helper_restore_fbdev_mode(helper); if (ret) error = true; + + mutex_unlock(&dev->mode_config.mutex); } return error; } -- cgit v1.2.3-70-g09d2 From 83c617c590feea1fd6e0dee35c3a78fe1bfe3535 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Tue, 29 Apr 2014 11:44:35 +0200 Subject: drm/fb: Fix typos Fix a few trivial typos in the framebuffer helper documentation. Signed-off-by: Thierry Reding Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_fb_helper.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/drm_fb_helper.c') diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 158d8e51db3d..e95ed5805f07 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -45,13 +45,13 @@ static LIST_HEAD(kernel_fb_helper_list); * DOC: fbdev helpers * * The fb helper functions are useful to provide an fbdev on top of a drm kernel - * mode setting driver. They can be used mostly independantely from the crtc + * mode setting driver. They can be used mostly independently from the crtc * helper functions used by many drivers to implement the kernel mode setting * interfaces. * * Initialization is done as a three-step process with drm_fb_helper_init(), * drm_fb_helper_single_add_all_connectors() and drm_fb_helper_initial_config(). - * Drivers with fancier requirements than the default beheviour can override the + * Drivers with fancier requirements than the default behaviour can override the * second step with their own code. Teardown is done with drm_fb_helper_fini(). * * At runtime drivers should restore the fbdev console by calling @@ -59,7 +59,7 @@ static LIST_HEAD(kernel_fb_helper_list); * should also notify the fb helper code from updates to the output * configuration by calling drm_fb_helper_hotplug_event(). For easier * integration with the output polling code in drm_crtc_helper.c the modeset - * code proves a ->output_poll_changed callback. + * code provides a ->output_poll_changed callback. * * All other functions exported by the fb helper library can be used to * implement the fbdev driver interface by the driver. -- cgit v1.2.3-70-g09d2