On Tue, Aug 21, 2018 at 7:59 AM, Noralf Trønnes <noralf@xxxxxxxxxxx> wrote: > Den 21.08.2018 10.44, skrev Daniel Vetter: >> On Mon, Aug 20, 2018 at 11:44:56PM -0700, John Stultz wrote: >>> >>> Since we don't have a drm_gem_cma_object reference in >>> drm_fb_helper_generic_probe(), I instead added: >>> fbi->fix.smem_start = page_to_phys(virt_to_page(fbi->screen_buffer)); >>> >>> And that got things working! >>> >>> So yea, I wanted to figure out if we are just missing the line above >>> in drm_fb_helper_generic_probe()? Or if the kirin driver should be >>> setting the fix.smem_start in some other fashion? >> >> With the generic helpers we can't use the generic fb_mmap() implementation >> in fbdev/core/fbmem.c anymore. Instead Noralf added a generic fb_mmap >> fb_ops callback in drm_fbdev_fb_mmap, which you're supposed to use. Can >> you pls double-check that this is wired up correctly for kirin? >> >> At least I don't see any other place where we use smem_start in the fbdev >> code. It does get copied to userspace, but userspace should never use >> that. > > > I googled 'FBIOGET_FSCREENINFO smem_start' and came across info[1] > about the Mali blob using it and HiKey seems to have a Mali GPU: > > 00:17 <ssvb> BorgCuba: > the mali blob is supposed to open the framebuffer device, > get "smem_start" and try to map this memory via MALI_IOC_MEM_MAP_EXT ioctl > > Could this be the problem here? It does look like that's the case. Looking for smem_start usage, for Android its the gralloc code that fetches it: https://android.googlesource.com/device/linaro/hikey/+/master/gralloc/framebuffer_device.cpp#353 and then puts it into the private_handle_t: https://android.googlesource.com/device/linaro/hikey/+/master/gralloc/framebuffer_device.cpp#384 Which I assume then gets used later in the opaque mali blob (which then results in a similarly opaque hang). While I'm perfectly understanding that folks are not interested as its related to mali (which is fine, I can carry a patch - working to move away from fbdev emulation anyway), I am wondering if it might cause trouble for other users, as smem_start was previously set and now its not, so it seems likely to break userspace examples like: https://www.linuxtv.org/downloads/v4l-dvb-apis-old/osd.html Or are those such old legacy they don't really count? thanks -john _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
