Hi,
A while back I had the idea to turn a Raspberry Pi Zero into a $5 USB to HDMI/SDTV/DPI display adapter.
The protocol is open so people are free to make displays implementing it and use this driver, all that's needed is to add a USB vid:pid to the driver for the display.
See the wiki[1] for more information and images for the Raspberry Pi Zero/4.
Changes in this version: - LZ4_compress_default() can return zero, check for that - Fix memory leak in gud_pipe_check() error path (Peter) - Improve debug and error messages (Peter) - Don't pass length in protocol structs (Peter) - Pass USB interface to gud_usb_control_msg() et al. (Peter) - Improve gud_connector_fill_properties() (Peter) - Add GUD_PIXEL_FORMAT_RGB111 (Peter) - Remove GUD_REQ_SET_VERSION (Peter) - Fix DRM_IOCTL_MODE_OBJ_SETPROPERTY and the rotation property - Fix dma-buf import (Thomas)
Note: There are several changes to the protocol.
I plan to apply the patches in a week or so unless something turns out to be broken.
Dependency: drm: Use USB controller's DMA mask when importing dmabufs[2] (currently in drm-misc-fixes but not in drm-misc-next yet, also present in drm-tip and linux-next)
Noralf.
[1] https://github.com/notro/gud/wiki [2] https://patchwork.freedesktop.org/patch/msgid/20210303133229.3288-1-tzimmerm...
Noralf Trønnes (3): drm/uapi: Add USB connector type drm/probe-helper: Check epoch counter in output_poll_execute() drm: Add GUD USB Display driver
MAINTAINERS | 8 + drivers/gpu/drm/Kconfig | 2 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_connector.c | 1 + drivers/gpu/drm/drm_probe_helper.c | 7 +- drivers/gpu/drm/gud/Kconfig | 14 + drivers/gpu/drm/gud/Makefile | 4 + drivers/gpu/drm/gud/gud_connector.c | 729 ++++++++++++++++++++++++++++ drivers/gpu/drm/gud/gud_drv.c | 659 +++++++++++++++++++++++++ drivers/gpu/drm/gud/gud_internal.h | 154 ++++++ drivers/gpu/drm/gud/gud_pipe.c | 535 ++++++++++++++++++++ include/drm/gud.h | 333 +++++++++++++ include/uapi/drm/drm_mode.h | 1 + 13 files changed, 2447 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/gud/Kconfig create mode 100644 drivers/gpu/drm/gud/Makefile create mode 100644 drivers/gpu/drm/gud/gud_connector.c create mode 100644 drivers/gpu/drm/gud/gud_drv.c create mode 100644 drivers/gpu/drm/gud/gud_internal.h create mode 100644 drivers/gpu/drm/gud/gud_pipe.c create mode 100644 include/drm/gud.h