Hi,
On Sun, Feb 03, 2019 at 10:54:55AM -0800, Vasily Khoruzhick wrote:
> Clock rate check that was added in commit bb43d40d7c83 ("drm/sun4i: rgb:
> Validate the clock rate") prevents some panel and bridges from working with
> sun4i driver.
>
> Unfortunately, dotclock frequency for some modes are not achievable on
> sunxi hardware, and there's a slight deviation in rate returned by
> clk_round_rate(), so they fail this check.
>
> Experiments show that panels and bridges work fine with this slight
> deviation, e.g. Pinebook that uses ANX6345 bridge with 768p eDP panel
> requests 73 MHz, gets 72.296MHz instead (0.96% difference) and works just
> fine.
>
> This patch adds a 1% tolerence to the dot clock check when bridge is
> connected.
>
> Signed-off-by: Vasily Khoruzhick <[email protected]>I'm not sure we want to make exceptions for all the hardware combination we face, but we should go for something more generic (and easier to maintain instead). IIRC, from the previous discussion, HDMI had a tolerancy requirement in the standard. Do you know if there's such a thing for eDP? That would solve the issue for all the eDP displays at once. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
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