Re: com(4) over 115200 bps support

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Mon, Mar 01, 2010 at 03:32:01PM +0900, KIYOHARA Takashi wrote:
> Hi! all,
> 
> 
> I want tester for attached patch.
> (This patch defines COM_16950 at head forcely. ;-)
> 
>   16650 supports max 460800 bps.  (perhaps ;-)
>   16950 supports max 921600 bps.
> 
> It support over 115200 bps with 16650 and 16950.
> I tested on hpcsh with Bluetooth PCMCIA card included 16950.  My card
> establish for 921600bps to me.
> 
> I am not convinced of 16650 correctly supporting it.  And, this patch
> was did not work with 'st16650 broken fifo' on my sandpoint(KURO-BOX:
> MPC8241 SoC).

The higher speeds do work on real 16650 parts.  But there's something
not right with our existing 16650 support -- it doesn't work with a 650
or 950 on a card for me.  It did work at some point in the past.

Be sure you are enabling the deeper FIFOs (automatic in some modes of
operation) on these chips -- they basically won't work at high speed
with the 16550 FIFO depth.  Also you may want to check that the code
for handling the automatic hardware flow control is working properly,
it would be my best guess for what's currently not right.

Thor