Messages in this thread | | | Date | Mon, 17 Apr 2023 22:07:56 +0200 | Subject | Re: [PATCH 5/6] drm: bridge: samsung-dsim: Support non-burst mode | From | Marek Vasut <> |
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On 4/17/23 13:57, Adam Ford wrote: > On Sun, Apr 16, 2023 at 5:13 PM Marek Vasut <marex@denx.de> wrote: >> >> On 4/15/23 12:41, Adam Ford wrote: >>> The high-speed clock is hard-coded to the burst-clock >>> frequency specified in the device tree. However, when >>> using devices like certain bridge chips without burst mode >>> and varying resolutions and refresh rates, it may be >>> necessary to set the high-speed clock dynamically based >>> on the desired pixel clock for the connected device. >> >> The link rate negotiation should happen internally between the nearest >> bridge and DSIM, so please add that to DRM core instead of hacking >> around it by tweaking the HS clock again. > > I thought you tried to add something like this before and had some resistance.
Yes, all my attempts were rejected by a single reviewer. I suspended my efforts in that area for now.
> The Pixel clock is set by the bridge already without any new code > added to the DRM core.. I am just reading that value that's there, > and setting the clock accordingly. I don't see how this is a hack.
Assume you have a DSI-to-HDMI bridge attached to your DSIM bridge, it operates in non-burst mode, like ADV7533 . How would you configure the HS clock rate for such a bridge in DT ? (hint: you cannot, because the required clock comes from the EDID, which may not be available just yet)
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