On Wed, Oct 21, 2020 at 03:07:29PM +0200, Thomas Zimmermann wrote:
The drivers gm12u320 and udl operate on USB devices. They leave the PCI device in struct drm_device empty and store the USB device in their own driver structure.
Fix this special case and save a few bytes by putting the USB device into an anonymous union with the PCI data. It's expected that DRM core and helpers only touch the PCI-device field for actual PCI devices.
Uh no.
If you're really concerned about the 8 bytes wasted, use drm_device->dev instead, and upcast it to the usb device. I think some drivers do this already (at least on the platform side iirc).
But we had this entire drm_bus midlayer stuff already, and it took forever to sunset it. I don't want to go back, and saving 8 bytes in a giantic structure isn't worth that risk imo. -Daniel
Thomas Zimmermann (3): drm: Add reference to USB device to struct drm_device drm/tiny/gm12u320: Store USB device in struct drm_device.udev drm/udl: Store USB device in struct drm_device.udev
drivers/gpu/drm/tiny/gm12u320.c | 52 +++++++++++++---------------- drivers/gpu/drm/udl/udl_connector.c | 8 ++--- drivers/gpu/drm/udl/udl_drv.c | 2 +- drivers/gpu/drm/udl/udl_drv.h | 1 - drivers/gpu/drm/udl/udl_main.c | 15 +++++---- include/drm/drm_device.h | 21 ++++++++---- 6 files changed, 52 insertions(+), 47 deletions(-)
-- 2.28.0