Re: [PATCH][MIPS][5/6]: AR7: serial hack

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Thomas Bogendoerfer wrote:

>>Il Saturday 15 March 2008 11:40:09 Thomas Bogendoerfer ha scritto:

>>>On Fri, Mar 14, 2008 at 04:46:09PM +0100, Matteo Croce wrote:

>>>>This is a bit better

>>>is it possible to try without the serial changes first ?

>>>Use 

>>>       uart_port[0].type = PORT_16550A;

>>>in arch/mips/ar7/platform.c.

>>>Does it work ?

>>Tried I get teh usual broken serial output:

> I just checked the latest AR7/UR8 source, I have, and they don't need
> special hacks. This is a 2.6.10 based tree. At that time there was
> no serial8250_console_putchar(), console output was done via
> serial8250_console_write() without any helper. Before writing to 
> the UART_TX, wait_for_xmitr() is called. And this wait_for_xmitr() does
> check for BOTH_EMPTY.

> Is there a good reason, why we don't check for BOTH_EMPTY in
> serial8250_console_putchar() ?

    I guess transmission will be slower if you check both THRE and TSRE 
conditions.

> To match the 2.6.10 behaviour we
> would need that and this would fix the AR7 case without any
> special handling.

    AR7 case seems to be the case of bad hardware, and so require special 
handling...

> Thomas.

WBR, Sergei