On Thu, Apr 5, 2018 at 9:16 AM, Alexey Brodkin
> 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.brod...@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  then indeed
> picture is displayed on the screen. But there I guess won't be any 3D
> At least that's what was suggested to me earlier here  by Lucas:
> For 3D acceleration to work under X you need the etnaviv specific DDX
> driver, which can be found here:
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.
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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