On Mon, Sep 14, 2015 at 04:12:29PM -0700, Rafael Antognolli wrote: > This is a tentative implementation of a module that allows reading/writing > arbitrary dpcd registers, following the suggestion from Daniel Vetter. It > assumes the drm aux helpers were used by the driver. > > I tried to follow the i2c-dev implementation as close as possible, but the only > operations that are provided on the dev node are two different ioctl's, one for > reading a register and another one for writing it. Why would you use ioctls instead of normal read/write syscalls? > > I have at least 2 open questions: > > * Right now the AUX channels are stored in a global list inside the > drm_dp_helper implementation, and I assume that's not ideal. A different > approach would be to iterate over the list of connectors, instead of the > list of AUX channels, but that would require the struct drm_connector or > similar to know about the respective aux helper. It could be added as a > function to register that, or as a new method on the drm_connector_funcs to > retrieve the aux channel helper. > > * From the created sysfs drm_aux-dev device it's possible to know what is the > respective connector, but not the other way around. Is this good enough? > > Please provide any feedback you have and tell me if this is the idea you had > initially for this kind of implementation. Or, if it's nothing like this, let > me know what else you had in mind. > > If I'm going in the right direction, I'll refine the patch to provide full > documentation and tests if needed. > > Rafael Antognolli (3): > drm/dp: Keep a list of drm_dp_aux helper. > drm/dp: Store the drm_connector device pointer on the helper. > drm/dp: Add a drm_aux-dev module for reading/writing dpcd registers. > > Documentation/ioctl/ioctl-number.txt | 1 + > drivers/gpu/drm/Kconfig | 4 + > drivers/gpu/drm/Makefile | 1 + > drivers/gpu/drm/drm_aux-dev.c | 390 +++++++++++++++++++++++++++++++++++ > drivers/gpu/drm/drm_dp_helper.c | 71 +++++++ > drivers/gpu/drm/i915/intel_dp.c | 1 + > include/drm/drm_dp_helper.h | 7 + > include/uapi/linux/Kbuild | 1 + > include/uapi/linux/drm_aux-dev.h | 45 ++++ > 9 files changed, 521 insertions(+) > create mode 100644 drivers/gpu/drm/drm_aux-dev.c > create mode 100644 include/uapi/linux/drm_aux-dev.h > > -- > 2.4.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
