On Fri, Feb 2, 2018 at 11:51 PM, Tomasz Figa <tf...@chromium.org> wrote: > On Fri, Feb 2, 2018 at 11:00 PM, Rob Herring <r...@kernel.org> wrote: >> On Fri, Feb 2, 2018 at 2:01 AM, Tomasz Figa <tf...@chromium.org> wrote: >>> Hi Rob, >>> >>> On Tue, Jan 30, 2018 at 9:36 PM, Robert Foss <robert.f...@collabora.com> >>> wrote: >>>>>>>>> uint32_t (*get_fd)(buffer_handle_t handle, uint32_t plane); >>>>>>>>> uint64_t (*get_modifier)(buffer_handle_t handle, uint32_t >>>>>>>>> plane); >>>>>>>>> uint32_t (*get_offsets)(buffer_handle_t handle, uint32_t plane); >>>>>>>>> uint32_t (*get_stride)(buffer_handle_t handle, uint32_t plane); >>>>>>>>> ... >>>>>>>>> } gralloc_funcs_t; >>>>> >>>>> >>>>> These ones? > >>>>> Yeah, if we could retrieve such function pointer struct using perform >>>>> or any equivalent (like the implementation-specific methods in >>>>> gralloc1, but not sure if that's going to be used in practice >>>>> anywhere), it could work for us. >>>> >>>> >>>> So this is where you and Rob Herring lose me, I don't think I understand >>>> quite how the gralloc1 call would be used, and how it would tie into this >>>> handle struct. I think I could do with some guidance on this. >>> >>> This would be very similar to gralloc0 perform call. gralloc1 >>> implementations need to provide getFunction() callback [1], which >>> returns a pointer to given function. The list of standard functions is >>> defined in the gralloc1.h header [2], but we could take some random >>> big number and use it for our function that fills in provided >>> gralloc_funcs_t struct with necessary pointers. >>> >>> [1] >>> https://android.googlesource.com/platform/hardware/libhardware/+/master/include/hardware/gralloc1.h#300 >>> [2] >>> https://android.googlesource.com/platform/hardware/libhardware/+/master/include/hardware/gralloc1.h#134 >> >> This is a deadend because it won't work with a HIDL based >> implementation (aka gralloc 2.0). You can't set function pointers (or >> any pointers) because gralloc runs in a different process. Yes, >> currently gralloc is a pass-thru HAL, but AIUI that will go away. > > Part of it. I can't see IMapper being implemented by a separate > process. You can't map a buffer into one process from another process. > > But anyway, it's a good point, thanks, I almost forgot about its > existence. I'll do further investigation.
Okay, so IMapper indeed breaks the approach I suggested. I'm not sure at the moment what we could do about it. (The idea of a dynamic library of a pre-defined name, exporting functions we specify, might still work, though.) Note that the DRM_GRALLOC_GET_FD used currently by Mesa will also be impossible to implement with IAllocator/IMapper. (Although I still think Mesa and Gralloc are free to have separate logic for choosing the DRM device to use.) Best regards, Tomasz _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
