On 02.03.20 09:44, Frieder Schrempf wrote: > On 26.02.20 17:05, Guido Günther wrote: >> On Wed, Feb 26, 2020 at 04:54:35PM +0100, Lucas Stach wrote: >>> On Mi, 2020-02-26 at 15:31 +0000, Schrempf Frieder wrote: >>>> On 25.02.20 09:13, Frieder Schrempf wrote: >>>>> Hi Lucas, >>>>> >>>>> On 24.02.20 12:08, Lucas Stach wrote: >>>>>> On Mo, 2020-02-24 at 10:53 +0000, Schrempf Frieder wrote: >>>>>>> Hi Lucas, >>>>>>> >>>>>>> On 24.02.20 11:37, Lucas Stach wrote: >>>>>>>> Hi Frieder, >>>>>>>> >>>>>>>> On Mo, 2020-02-24 at 10:28 +0000, Schrempf Frieder wrote: >>>>>>>>> On 20.02.20 19:58, Chris Healy wrote: >>>>>>>>>> For the jerkey transitions, can you determine if this is a >>>>>>>>>> symptom of >>>>>>>>>> a low framerate or dropped frames or something else? >>>>>>>>>> >>>>>>>>>> Perhaps you can start your app with >>>>>>>>>> "GALLIUM_HUD=fps,cpu,draw-calls,frametime". This may give some >>>>>>>>>> clues. >>>>>>>>> >>>>>>>>> The framerate seems ok. I get something between 50 and 70 FPS. >>>>>>>>> >>>>>>>>> I have a Qt demo app with a menu and an animated 'ball' that moves >>>>>>>>> across the screen. When the menu is visible, the ball movement is >>>>>>>>> really >>>>>>>>> jerky (ball seems to 'jump back and forth' instead of moving >>>>>>>>> linearly). >>>>>>>>> >>>>>>>>> As soon as I hide the menu and show the animation fullscreen, the >>>>>>>>> movements are perfectly smooth. >>>>>>>>> >>>>>>>>> Running the same app with software rendering, everything looks >>>>>>>>> good, too. >>>>>>>>> >>>>>>>>> No idea what that means, though. I probably need to look at the >>>>>>>>> code of >>>>>>>>> the app and do some more experiments to get a better idea of what >>>>>>>>> might >>>>>>>>> cause the distortion. >>>>>>>>> >>>>>>>>> Unless some of the graphics experts here already have an idea >>>>>>>>> of what >>>>>>>>> can cause and/or how to debug such an issue!? >>>>>>>> >>>>>>>> Which driver is used for the display side? It seems like the >>>>>>>> display >>>>>>>> side doesn't properly handle the dma fences used to synchronize >>>>>>>> scanout >>>>>>>> and rendering. >>>>>>> >>>>>>> I ported/picked the drivers for the LCDIF and DSI controllers from >>>>>>> development branch of the 5.4-based vendor kernel [1] to our own >>>>>>> v5.4-based kernel [2]. So it is quite probable, that something >>>>>>> could be >>>>>>> wrong here. >>>>>> >>>>>> Please just use DRM_MXSFB for the display side, instead of the >>>>>> downstream driver. >>>>> >>>>> Hm, good idea. I somehow forgot about the fact, that there is an >>>>> upstream driver for the LCDIF controller. On first try I couldn't >>>>> get it >>>>> to run on the i.MX8MM, but I suspect that's due to some reset, >>>>> power-domain or clock setup, that is missing upstream. I will see if I >>>>> can get any further with this. >>>> >>>> So I had a closer look and while the DRM_MXSFB looks ok on its own, I >>>> have some problem with the rest of the i.MX8MM display subsystem. >>>> >>>> The vendor stack, that I'm currently using integrates into the imx-drm >>>> master/core driver [1] that binds all the components of the display >>>> subsystem, such as the LCDIF driver and the integrated SEC_DSIM DSI >>>> bridge. >>>> >>>> And because of my lack of DRM skills, I have no idea how to get the >>>> DRM_MXSFB driver to bind to the imx-drm core, instead of running >>>> separately and connecting directly to some panel as it is done for >>>> i.MX23/28 and i.MX6SX/UL. >>> >>> It's a separate hardware and it's a pretty major design issue of the >>> downstream driver that it integrates into imx-drm. You don't want this >>> with the upstream driver. >>> >>> Maybe Guido (CCed) can give you some clues, as apparently he is using >>> the mainline eLCDIF driver + some patches to drive the DSI display path >>> on i.MX8MQ. A lot of this will probably be transferable to the i.MX8MM >>> display path. >> >> Newer mxsfb supports attaching a bridge so if you make your DSI host >> controller driver a DSI bridge mxsfb can drive it: >> >> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/mxsfb/mxsfb_drv.c#n268 >> >> >> this should be similar to what was done for the imx8mq here (imx8mm >> users a different ip core though): >> >> >> https://source.puri.sm/guido.gunther/linux-imx8/commits/forward-upstream/next-20200217/mxsfb+nwl/v9-wip >> >> >> There's also some additional mxsfb patches by Robert floating around >> which aren't mainline yet which the above branch also has. >> >> Which reminds me that i need to prepare and send out a v9. > > Thanks Lucas and Guido for pointing out the details! > It's very unfortunate that i.MX8MQ and i.MX8MM don't share the same DSI > ip core. > It seems like I need to try coming up with a bridge driver for the > Samsung DSIM DSI controller for a proper upstream solution. Sorry to bother you with one more question from a DRM newbie. I'm currently looking at Guido's code for the NWL DSI bridge and trying to convert the NXP SEC DSIM host driver to a bridge driver. The NWL driver uses mipi_dsi_host_register(), which searches for a output (panel) child node under the DSI bridge's node [1] as described in the bindings example [2]. How is this supposed to work in a setup with another bridge after the DSI bridge, where that bridge is not a child node of the DSI bridge, but only connected via the DSI bridges output port? For example I have a DSI->LVDS bridge, that is attached to an I2C port. [1] https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_mipi_dsi.c#L284 [2] https://source.puri.sm/guido.gunther/linux-imx8/blob/forward-upstream/next-20200226/mxsfb+nwl/v9-wip/Documentation/devicetree/bindings/display/bridge/nwl-dsi.yaml#L173 Thanks, Frieder _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
