On 3/3/22 21:58, Thomas Zimmermann wrote:
Provide struct drm_driver.dumb_create_fbdev, a callback hook for fbdev dumb buffers. Wire up fbdev and client helpers to use the new interface, if present.
This acknowledges the fact that fbdev buffers are different. The most significant difference to regular GEM BOs is in mmap semantics. Fbdev userspace treats the pages as video memory, which makes it impossible to ever move the mmap'ed buffer. Hence, drivers ussually have to pin the BO permanently or install an intermediate shadow buffer for mmap.
So far, fbdev memory came from dumb buffers and DRM drivers had no means of detecting this without reimplementing a good part of the fbdev code. With the new callback, drivers can perma-pin fbdev buffer objects if needed.
Several drivers also require damage handling, which fbdev implements with its deferred I/O helpers. The new callback allows a driver's memory manager to set up a suitable mmap.
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de
drivers/gpu/drm/drm_client.c | 14 +++++++---- drivers/gpu/drm/drm_crtc_internal.h | 3 +++ drivers/gpu/drm/drm_dumb_buffers.c | 36 +++++++++++++++++++++++++---- drivers/gpu/drm/drm_fb_helper.c | 26 +++++++++++++++++---- include/drm/drm_client.h | 3 ++- include/drm/drm_drv.h | 17 ++++++++++++++ 6 files changed, 84 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c index af3b7395bf69..c964064651d5 100644 --- a/drivers/gpu/drm/drm_client.c +++ b/drivers/gpu/drm/drm_client.c @@ -247,7 +247,8 @@ static void drm_client_buffer_delete(struct drm_client_buffer *buffer) }
static struct drm_client_buffer * -drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format) +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format,
bool fbdev){ const struct drm_format_info *info = drm_format_info(format); struct drm_mode_create_dumb dumb_args = { }; @@ -265,7 +266,10 @@ drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u dumb_args.width = width; dumb_args.height = height; dumb_args.bpp = info->cpp[0] * 8;
- ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
- if (fbdev)
Maybe if (defined(CONFIG_DRM_FBDEV_EMULATION) && fbdev) ?
ret = drm_mode_create_dumb_fbdev(dev, &dumb_args, client->file);
And drm_mode_create_dumb_fbdev() could just be made a stub if CONFIG_DRM_FBDEV_EMULATION isn't enabled.
I believe the only usage of the DRM client API currently is the fbdev emulation layer anyways? But still makes sense I think to condtionally compile that since drm_client.o is built in the drm.ko module and the drm_fb_helper.o only included if fbdev emulation has been enabled.
- else
ret = drm_mode_create_dumb(dev, &dumb_args, client->file);@@ -402,6 +406,7 @@ static int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
- @width: Framebuffer width
- @height: Framebuffer height
- @format: Buffer format
- @fbdev: True if the client provides an fbdev device, or false otherwise
An emulated fbdev device ?
Other than those small nit,
Reviewed-by: Javier Martinez Canillas javierm@redhat.com