[Libdlo] [PATCH] Fix displaylink-mod with 2.6.32

[Andrew Kephart]

On Thu, 2010-12-09 at 13:32 -0800, Bernie Thompson wrote:
> Hi Jonathan,
[some text deleted]

> In all recent versions of udlfb the mode is selected this way:
> 
> 1) We start from the monitor's preferred mode (assuming this monitor's
> EDID reported 1680x1050)
> 2) We look at a DisplayLink-specific USB descriptor (in the device's
> firmware) to read the device's maximum mode
> 3) If the device can't do the monitor's preferred mode, we (call fbdev
> functions to) pick the best lower alternative mode listed in the EDID
> 
[some text deleted]

Not that it matters to the vast majority of folks out there, but there
is a bug in fb_find_nearest_mode(), where it will pick the wrong mode if
the nearest refresh rate is in the first mode encountered at the nearest
resolution.  For example, if your target is 800x600x60 and the available
modes are 800x600x60 and 800x600x72, it will return the latter, even
though the former is a perfect match.  This should only be a problem if
the EDID read fails and the target monitor can't handle the higher
refresh rates, though.

I was going to submit the patch to linux-fbdev, but can add it here,
too, if anyone is interested.

-andrew

> > J.
> 
> Thanks,
> Bernie
> http://plugable.com/
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