Re: [PATCH 06/13] USB: serial: ch341: fix initial line settings

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On Wed, Dec 14, 2016 at 3:28 PM, Johan Hovold <johan@xxxxxxxxxx> wrote:
> The ch341 driver is based on reverse-engineering and contains some bits
> which appear to be redundant and some which appear incompatible which
> certain devices.
>
> Specifically, some CH340 devices seem unable to change the initial line
> settings, which have so far been set to 5N1. Let's use a more reasonable
> 8N1 default instead.
>
> Note that we also need to set the ENABLE_RX bit or receive will be
> disabled after a reset during resume.

Lost track a little of the testing, but I don't think you ever got
Russel to test whether this worked using a driver that tried to change
this through direct register writes which seem to be the only thing
that has any effect on this strange hardware variant. Would be a
little surprised if it didn't at this point - changing the line
settings that way after initialization certainly works well enough to
cause us all a headache.

If so, I suggest it might be clearer to drop this patch altogether in
favour of patch 10 in the series, since the underlying problem is that
setting the baudrate and LCR register didn't work and patch 10 fixes
that.
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