Hi Michael, On 28.08.23 17:59, Michael Tretter wrote: > I tested the i.MX8M Nano EVK with the NXP supplied MIPI-DSI adapter, > which uses an ADV7535 MIPI-DSI to HDMI converter. I found that a few > modes were working, but in many modes my monitor stayed dark. > > This series fixes the Samsung DSIM bridge driver to bring up a few more > modes: > > The driver read the rate of the PLL ref clock only during probe. > However, if the clock is re-parented to the VIDEO_PLL, changes to the > pixel clock have an effect on the PLL ref clock. Therefore, the driver > must read and potentially update the PLL ref clock on every modeset. > > I also found that the rounding mode of the porches and active area has > an effect on the working modes. If the driver rounds up instead of > rounding down and be calculates them in Hz instead of kHz, more modes > start to work. > > The following table shows the modes that were working in my test without > this patch set and the modes that are working now: > > | Mode | Before | Now | > | 1920x1080-60.00 | X | X | > | 1920x1080-59.94 | | X | > | 1920x1080-50.00 | | X | > | 1920x1080-30.00 | | X | > | 1920x1080-29.97 | | X | > | 1920x1080-25.00 | | X | > | 1920x1080-24.00 | | | > | 1920x1080-23.98 | | | > | 1680x1050-59.88 | | X | > | 1280x1024-75.03 | X | X | > | 1280x1024-60.02 | X | X | > | 1200x960-59.99 | | X | > | 1152x864-75.00 | X | X | > | 1280x720-60.00 | | | > | 1280x720-59.94 | | | > | 1280x720-50.00 | | X | > | 1024x768-75.03 | | X | > | 1024x768-60.00 | | X | > | 800x600-75.00 | X | X | > | 800x600-60.32 | X | X | > | 720x576-50.00 | X | X | > | 720x480-60.00 | | | > | 720x480-59.94 | X | | > | 640x480-75.00 | X | X | > | 640x480-60.00 | | X | > | 640x480-59.94 | | X | > | 720x400-70.08 | | | > > Interestingly, the 720x480-59.94 mode stopped working. However, I am > able to bring up the 720x480 modes by manually hacking the active area > (hsa) to 40 and carefully adjusting the clocks, but something still > seems to be off. > > Unfortunately, a few more modes are still not working at all. The NXP > downstream kernel has some quirks to handle some of the modes especially > wrt. to the porches, but I cannot figure out, what the driver should > actually do in these cases. Maybe there is still an error in the > calculation of the porches and someone at NXP can chime in. Thanks for working on this! We tested these patches with our Kontron BL i.MX8MM board and a "10.1inch HDMI LCD (E)" display from Waveshare [1]. Without this series we don't get an image with the default mode of the display (1024x600). With this series applied, it's now working. For the whole series: Tested-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> # Kontron BL i.MX8MM + Waveshare 10.1inch HDMI LCD (E) Thanks Frieder [1] https://www.waveshare.com/10.1inch-hdmi-lcd-e.htm
