Hi Daniel, Sorry to bother you again. I promise this is the last time :) On 15-06-2016 11:15, Daniel Vetter wrote: > On Wed, Jun 15, 2016 at 11:48 AM, Jose Abreu <Jose.Abreu@xxxxxxxxxxxx> wrote: >> On 15-06-2016 09:52, Daniel Vetter wrote: >>> On Tue, Jun 14, 2016 at 1:19 PM, Jose Abreu <Jose.Abreu@xxxxxxxxxxxx> wrote: >>>>> I assume that xilinx VDMA is the only way to feed pixel data into your >>>>> display pipeline. Under that assumption: >>>>> >>>>> drm_plane should map to Xilinx VDMA, and the drm_plane->drm_crtc link >>>>> would represent the dma channel. With atomic you can subclass >>>>> drm_plane/crtc_state structures to store all the runtime configuration in >>>>> there. >>>>> >>>>> The actual buffer itsel would be represented by a drm_framebuffer, which >>>>> either wraps a shmem gem or a cma gem object. >>>>> >>>>> If you want to know about the callbacks used by the atomic helpers to push >>>>> out plane updates, look at the hooks drm_atomic_helper_commit_planes() >>>>> (and the related functions, see kerneldoc) calls. >>>>> >>>>> I hope this helps a bit more. >>>>> -Daniel >>>> Thanks a lot! With your help I was able to implement all the >>>> needed logic. Sorry to bother you but I have one more question. >>>> Right now I can initialize and configure the vdma correctly but I >>>> can only send one frame. I guess when the dma completes >>>> transmission I need to ask drm for a new frame, right? Because >>>> the commit function starts the vdma correctly but then the dma >>>> halts waiting for a new descriptor. >>> DRM has a continuous scanout model, i.e. when userspace doesn't give >>> you a new frame you're supposed to keep scanning out the current one. >>> So you need to rearm your upload code with the same drm_framebuffer if >>> userspace hasn't supplied a new one since the last time before the >>> vblank period starts. >>> >>> This is different to v4l, where userspace has to supply each frame >>> (and the kernel gets angry when there's not enough frames and signals >>> an underrun of the queue). This is because drm is geared at desktops, >>> and there it's perfectly normal to show the exact same frame for a >>> long time. >>> -Daniel >> Thanks, I was thinking this was similar to v4l. I am now able to >> send multiple frames so it is finally working! I have one little >> implementation detail: The controller that I am using supports >> deep color mode but I am using FB CMA helpers to create the >> framebuffer and I've seen that the supported bpp in these helpers >> only goes up to 32, right? Does this means that with these >> helpers I can't use deep color? Can I implement this deep color >> mode (48bpp) using a custom fb or do I also need custom gem >> allocation functions (Right now I am using GEM CMA helpers)? > Suprising the cma doesn't take pixel_format into account. If this > really doesn't work, pls fix up the cma helpers, not roll your own > copypasta ;-) > > Note that the fbdev emulation itself (maybe that's what threw you off) > only supports legacy rgb formats up to 32bits. But native kms can > support anything, we just might need to add the DRM_FOURCC codes for > that. > -Daniel So, I ended up using 32bits and everything is working fine! I tested using [1] and [2] but now I have kind of a dumb question: I want to use the new driver that I created as a secondary output of my desktop so that I can play videos using mplayer but I am not being able to do this. If I check in my linux settings only one display is being detected, although in /dev/dri the two video cards are present (the native one and the one I added). Does the driver needs something additional to do this or is it only in my X configuration? I tried editing this configuration but still doesn't work. I believe that because my driver is not being probed at runtime the display is not being created by X. Is this correct? [1] https://dri.freedesktop.org/libdrm/ [2] https://github.com/dvdhrm/docs/blob/master/drm-howto/modeset.c Thanks! Best regards, Jose Miguel Abreu _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
