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| author | Thomas Zimmermann <tzimmermann@suse.de> | 2022-05-02 17:25:14 +0300 |
|---|---|---|
| committer | Thomas Zimmermann <tzimmermann@suse.de> | 2022-05-05 10:18:54 +0300 |
| commit | 931e3f3a0e997c41eafbc88e4fc07ba9fef28f29 (patch) | |
| tree | 435c7eafdc66bc24e65a3f5bb84ca5a9cc07de59 /drivers/gpu/drm/mgag200/mgag200_mode.c | |
| parent | f870231fdd6ce2c6c040a3584a2eac97ae473780 (diff) | |
| download | linux-931e3f3a0e997c41eafbc88e4fc07ba9fef28f29.tar.xz | |
drm/mgag200: Protect concurrent access to I/O registers with lock
Add a mutex lock to protect concurrent access to I/O registers
against each other. This happens between invocation of commit-
tail functions and get-mode operations. Both with use the CRTC
index registers MGA1064_GEN_IO_DATA and MGA1064_GEN_IO_CTL.
Concurrent access can lead to failed mode-setting operations.
v2:
* fix typo in commit description (Jocelyn)
* add comment to explain rmmio_lock
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220502142514.2174-4-tzimmermann@suse.de
Diffstat (limited to 'drivers/gpu/drm/mgag200/mgag200_mode.c')
| -rw-r--r-- | drivers/gpu/drm/mgag200/mgag200_mode.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c index 6e18d3bbd720..abde7655477d 100644 --- a/drivers/gpu/drm/mgag200/mgag200_mode.c +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c @@ -881,6 +881,14 @@ mgag200_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe, .y2 = fb->height, }; + /* + * Concurrent operations could possibly trigger a call to + * drm_connector_helper_funcs.get_modes by trying to read the + * display modes. Protect access to I/O registers by acquiring + * the I/O-register lock. + */ + mutex_lock(&mdev->rmmio_lock); + if (mdev->type == G200_WB || mdev->type == G200_EW3) mgag200_g200wb_hold_bmc(mdev); @@ -904,6 +912,8 @@ mgag200_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe, mgag200_enable_display(mdev); mgag200_handle_damage(mdev, fb, &fullscreen, &shadow_plane_state->data[0]); + + mutex_unlock(&mdev->rmmio_lock); } static void @@ -963,8 +973,12 @@ mgag200_simple_display_pipe_update(struct drm_simple_display_pipe *pipe, if (!fb) return; + mutex_lock(&mdev->rmmio_lock); + if (drm_atomic_helper_damage_merged(old_state, state, &damage)) mgag200_handle_damage(mdev, fb, &damage, &shadow_plane_state->data[0]); + + mutex_unlock(&mdev->rmmio_lock); } static struct drm_crtc_state * |