On Thu, Apr 5, 2018 at 9:16 AM, Alexey Brodkin <Alexey.Brodkin at synopsys.com> wrote: > Hi Daniel, > > On Thu, 2018-04-05 at 08:18 +0200, Daniel Vetter wrote: >> On Wed, Apr 4, 2018 at 10:06 PM, Alexey Brodkin >> <Alexey.Brodkin at synopsys.com> wrote: >> > Hello, >> > >> > We're trying to use DisplayLink USB2-to-HDMI adapter to render GPU-accelerated graphics. >> > Hardware setup is as simple as a devboard + DisplayLink adapter. >> > Devboards we use for this experiment are: >> > * Wandboard Quad (based on IMX6 SoC with Vivante GPU) or >> > * HSDK (based on Synopsys ARC HS38 SoC with Vivante GPU as well) >> > >> > I'm sure any other board with DRM supported GPU will work, those we just used >> > as the very recent Linux kernels could be easily run on them both. >> > >> > Basically the problem is UDL needs to be explicitly notified about new data >> > to be rendered on the screen compared to typical bit-streamers that infinitely >> > scan a dedicated buffer in memory. >> > >> > In case of UDL there're just 2 ways for this notification: >> > 1) DRM_IOCTL_MODE_PAGE_FLIP that calls drm_crtc_funcs->page_flip() >> > 2) DRM_IOCTL_MODE_DIRTYFB that calls drm_framebuffer_funcs->dirty() >> > >> > But neither of IOCTLs happen when we run Xserver with xf86-video-armada driver >> > (see https://urldefense.proofpoint.com/v2/url?u=http-3A__git.arm.linux.org.uk_cgit_xf86-2Dvideo-2Darmada.git_log_-3Fh-3Dunstable-2Ddevel&d=DwIBaQ&; >> > c=DPL6_X_6JkXFx7AXWqB0tg&r=lqdeeSSEes0GFDDl656eViXO7breS55ytWkhpk5R81I&m=oEAlP64L9vkuUs_k3kGwwwlN1WJbDMJbCo0uDhwKwwk&s=3ZHj- >> > 6JXZBLSTWg_4KMnL0VNi7z8c0RxHzj2U5ywVIw&e=). >> > >> > Is it something missing in Xserver or in UDL driver? >> >> Use the -modesetting driverr for UDL, that one works correctly. > > If you're talking about "modesetting" driver of Xserver [1] then indeed > picture is displayed on the screen. But there I guess won't be any 3D acceleration. > > At least that's what was suggested to me earlier here [2] by Lucas: > ---------------------------->8--------------------------- > For 3D acceleration to work under X you need the etnaviv specific DDX > driver, which can be found here: > > http://git.arm.linux.org.uk/cgit/xf86-video-armada.git/log/?h=unstable-devel You definitely want to use -modesetting for UDL. And I thought with glamour and the corresponding mesa work you should also get accelaration. Insisting that you must use a driver-specific ddx is broken, the world doesn't work like that anymore. Lucas, can you pls clarify? Also, why does -armada bind against all kms drivers, that's probaly too much. -Daniel > ---------------------------->8--------------------------- > > [1] https://cgit.freedesktop.org/xorg/xserver/tree/hw/xfree86/drivers/modesetting > [2] http://lists.infradead.org/pipermail/linux-snps-arc/2017-November/003031.html > > -Alexey -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
