On 2016-04-30 18:21, Greg KH wrote:
On Sat, Apr 30, 2016 at 03:56:08AM +0200, Grigori Goronzy wrote:
just a short question, what is the story with DTR/DSR flow control
under
Linux? It looks like Red Hat implemented this at some point [1], but
it
never went upstream. CH340/CH341 chipsets supports it (and probably
others
as well), so I was wondering.
It should work just fine, that Red Hat bug was just someone backporting
the upstream kernel support to their very old kernel release.
That's not really true. The patches in that Red Hat bug tracker backport
the termiox API, but they also implement DTR/DSR flow control for 8250
hardware. The upstream kernel doesn't have that driver implementation.
In fact, the termiox API is not used by a single driver and its support
code is dead code! I wasn't sure if it is abandoned. Seems really
strange either way.
Have you tried it?
Not yet, but if the termiox API is the way to go, I'll give that a try.
Grigori
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