There are no users of drm_fb_helper_defio_init(), so we can remove
it. The documenation around defio support is a bit misleading and
should mention compatibility issues with SHMEM helpers. Clarify this.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 61 +++++++--------------------------
include/drm/drm_fb_helper.h | 1 -
2 files changed, 13 insertions(+), 49 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index b75ae8555baf..8ebeccdeed23 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -92,9 +92,12 @@ static DEFINE_MUTEX(kernel_fb_helper_lock);
*
* Drivers that support a dumb buffer with a virtual address and mmap support,
* should try out the generic fbdev emulation using drm_fbdev_generic_setup().
+ * It will automatically set up deferred I/O if the driver requires a shadow
+ * buffer.
*
- * Setup fbdev emulation by calling drm_fb_helper_fbdev_setup() and tear it
- * down by calling drm_fb_helper_fbdev_teardown().
+ * For other drivers, setup fbdev emulation by calling
+ * drm_fb_helper_fbdev_setup() and tear it down by calling
+ * drm_fb_helper_fbdev_teardown().
*
* At runtime drivers should restore the fbdev console by using
* drm_fb_helper_lastclose() as their &drm_driver.lastclose callback.
@@ -127,8 +130,10 @@ static DEFINE_MUTEX(kernel_fb_helper_lock);
* 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. Drivers can use drm_fb_helper_defio_init() to setup
- * deferred I/O (coupled with drm_fb_helper_fbdev_teardown()).
+ * mmap page writes.
+ *
+ * Deferred I/O is not compatible with SHMEM. Such drivers should request an
+ * fbdev shadow buffer and call drm_fbdev_generic_setup() instead.
*/
static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
@@ -679,49 +684,6 @@ void drm_fb_helper_deferred_io(struct fb_info *info,
}
EXPORT_SYMBOL(drm_fb_helper_deferred_io);
-/**
- * drm_fb_helper_defio_init - fbdev deferred I/O initialization
- * @fb_helper: driver-allocated fbdev helper
- *
- * This function allocates &fb_deferred_io, sets callback to
- * drm_fb_helper_deferred_io(), delay to 50ms and calls fb_deferred_io_init().
- * It should be called from the &drm_fb_helper_funcs->fb_probe callback.
- * drm_fb_helper_fbdev_teardown() cleans up deferred I/O.
- *
- * NOTE: A copy of &fb_ops is made and assigned to &info->fbops. This is done
- * because fb_deferred_io_cleanup() clears &fbops->fb_mmap and would thereby
- * affect other instances of that &fb_ops.
- *
- * Returns:
- * 0 on success or a negative error code on failure.
- */
-int drm_fb_helper_defio_init(struct drm_fb_helper *fb_helper)
-{
- struct fb_info *info = fb_helper->fbdev;
- struct fb_deferred_io *fbdefio;
- struct fb_ops *fbops;
-
- fbdefio = kzalloc(sizeof(*fbdefio), GFP_KERNEL);
- fbops = kzalloc(sizeof(*fbops), GFP_KERNEL);
- if (!fbdefio || !fbops) {
- kfree(fbdefio);
- kfree(fbops);
- return -ENOMEM;
- }
-
- info->fbdefio = fbdefio;
- fbdefio->delay = msecs_to_jiffies(50);
- fbdefio->deferred_io = drm_fb_helper_deferred_io;
-
- *fbops = *info->fbops;
- info->fbops = fbops;
-
- fb_deferred_io_init(info);
-
- return 0;
-}
-EXPORT_SYMBOL(drm_fb_helper_defio_init);
-
/**
* drm_fb_helper_sys_read - wrapper around fb_sys_read
* @info: fb_info struct pointer
@@ -2356,7 +2318,10 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = {
*
* Drivers that set the dirty callback on their framebuffer will get a shadow
* fbdev buffer that is blitted onto the real buffer. This is done in order to
- * make deferred I/O work with all kinds of buffers.
+ * make deferred I/O work with all kinds of buffers. A shadow buffer can be
+ * requested explicitly by setting struct drm_mode_config.prefer_shadow or
+ * struct drm_mode_config.prefer_shadow_fbdev to true beforehand. This is
+ * required to use generic fbdev emulation with SHMEM helpers.
*
* This function is safe to call even when there are no connectors present.
* Setup will be retried on the next hotplug event.
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 8dcc012ccbc8..2338e9f94a03 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -235,7 +235,6 @@ 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);
-int drm_fb_helper_defio_init(struct drm_fb_helper *fb_helper);
ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
size_t count, loff_t *ppos);
--
2.23.0
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