On Tue, Mar 29, 2016 at 8:43 AM, Rob Clark <robdcl...@gmail.com> wrote: > On Mon, Mar 28, 2016 at 12:29 PM, Rob Herring <r...@kernel.org> wrote: >> On Fri, Mar 25, 2016 at 8:38 PM, Stéphane Marchesin <marc...@google.com> >> wrote: >>> On Wed, Mar 23, 2016 at 5:22 PM, Rob Herring <r...@kernel.org> wrote: >>>> On Fri, Mar 4, 2016 at 12:07 PM, Rob Clark <robdcl...@gmail.com> wrote: >>>>> On Fri, Mar 4, 2016 at 12:59 PM, Rob Clark <robdcl...@gmail.com> wrote: >>>>>> So, I've been advocating that for android, gallium drivers use >>>>>> gralloc_drm_pipe, since with android it seems like you end up with >>>>>> both gralloc and libGL in the same process, and having both share the >>>>>> same pipe_screen avoids lots of headaches with multiple gem handles >>>>>> pointing to same underlying buffer. >>>>>> >>>>>> But the awkward thing is that gralloc_drm_pipe is using gallium APIs >>>>>> that aren't particularly intended to be used out-of-tree. Ie. not >>>>>> really stable APIs. At the time, the thing that made sense to me was >>>>>> to pull drm_gralloc into mesa. But at the time, there were no >>>>>> non-mesa users of drm_gralloc, which isn't really true anymore. >>>>>> >>>>>> Maybe what makes more sense now is to implement a gralloc state >>>>>> tracker, which exposes a stable API for drm_gralloc? It would mostly >>>>>> be a shim to expose gallium import/export/transfer APIs in a stable >>>>>> way, but would also be where the code that figures out which driver to >>>>>> use to create/get the pipe_screen. >>>>> >>>>> and actually, we might just be able to use XA state tracker for this.. >>>>> I think it exposes all the necessary import/export/etc stuff that >>>>> gralloc would need.. >>>> >>>> Rob and I discussed this a bit more F2F recently. An alternative we >>>> discussed would be using GBM instead. GBM seems more inline with >>>> gralloc needs. This would also have the advantage of working with >>>> minigbm as well for non-mesa cases. Any thoughts on GBM vs. XA? >>> >>> gbm as it is misses some bits, for example lock/unlock, and more fine >>> grained usage flags. >> >> I think this can be implemented on top within gralloc as it is today >> with drm_gralloc. >> >> However, I found a bigger mismatch is there are no explicit map/unmap >> calls in GBM. A writeable buffer will be a dumb buffer and is >> implicitly mapped. Maybe that is enough in reality? >> > > I think originally this was probably just used for uploading mouse > cursor, or something along those lines, rather than any serious use of > sw rendering. But if android needs to mix hw and sw access to the > buffer, I think we do need something that maps to transfer_map/unmap, > so gl driver can (if needed) flush pending rendering and sync. > > Not sure how others feel, but I wouldn't be opposed to extending gbm.. > anything that can sit on top of transfer_map/unmap should coexist well > with a gpu driver.
Looks like it was tried already[1]. Interestingly, the gralloc lock interface already does some of what is discussed being needed (specifying the region). Rob [1] https://lists.freedesktop.org/archives/mesa-dev/2014-April/058484.html _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
