On Sun, 9 Sep 2012 22:03:14 -0500 Rob Clark rob.clark@linaro.org wrote:
From: Rob Clark rob@ti.com
The 'atomic' mechanism allows for multiple properties to be updated, checked, and commited atomically. This will be the basis of atomic- modeset and nuclear-pageflip.
The basic flow is:
state = dev->atomic_begin(); for (... one or more ...) obj->set_property(obj, state, prop, value); if (dev->atomic_check(state)) dev->atomic_commit(state, event); dev->atomic_end(state);
I think the above is more suited to drm_crtc_helper code. I think the top level callback should contain the arrays and be a single "multi flip" hook (or maybe a check then set double callback). For some drivers that'll end up being a lot simpler, rather than sprinkling atomic handling code in all the set_property callbacks.
Having a transactional API just seems a little messier with both the atomic state and per-property state to track and rollback in the case of failure.