On Thu, Oct 26, 2023 at 1:12 PM Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> wrote: > > Hi Adam, > > On 13.10.23 05:10, Adam Ford wrote: > > When using video sync pulses, the HFP, HBP, and HSA are divided between > > the available lanes if there is more than one lane. For certain > > timings and lane configurations, the HFP may not be evenly divisible > > and it gets rounded down which can cause certain resolutions and > > refresh rates to not sync. > > > > ie. 720p60 on some monitors show hss of 1390 and hdisplay of 1280. This > > yields an HFP of 110. When taking the HFP of 110 divides along 4 lanes, > > the result is 27.5 which rounds down to 27 and causes some monitors not > > to sync. > > > > The solultion is to round HFP up by finding the remainder of HFP / > > the number of lanes and increasing the hsync_start, hsync_end, and > > htotal to compensate when there is a remainder. > > > > Signed-off-by: Adam Ford <aford173@xxxxxxxxx> > > --- > > This adds support for 720p60 in the i.MX8M Plus. > > > > NXP uses a look-up table in their downstream code to accomplish this. > > Using this calculation, the driver can adjust without the need for a > > complicated table and should be flexible for different timings and > > resolutions depending on the monitor. > > > > I don't have a DSI analyzer, and this appears to only work on > > i.MX8M Plus but not Mini and Nano for some reason, despite their > > having a similar DSI bridge. > > I just want to report that I have tested this patch (on top of current > linux-next) on our Kontron BL i.MX8MM board with the ADV7535 bridge and > I don't see any change when trying the 30 different modes the monitor > reports as supported. 18 of those work and 12 don't work. Thanks for testing this. I didn't see any regressions on my Mini or Nano either, but I did see the 720p60 now works on i.MX8M Plus (but not on Mini/Nano). I am not sure why, and I don't have a DSI analyzer. > > So at least there is no negative impact in this case. At least nothing broke. :-) > > Tested-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> # Kontron BL > i.MX8MM with HDMI monitor I'll add your T-b when I post it again. > > Thanks > Frieder
