Re: [PATCH] Fix SCI console output

SUGIOKA Toshinobu
2009-06-01T11:34:52Z

At 13:59 09/06/01 +0900, Paul Mundt <lethal@linux-sh.org> wrote:
>On Mon, Jun 01, 2009 at 12:53:41PM +0900, SUGIOKA Toshinobu wrote:
>> Fix SCI transmission sequence in console output function.
>>
>> Signed-off-by: Toshinobu Sugioka <sugioka@itonet.co.jp>
>>
>This change was intentional. Do you have a use case where this causes a
>problem?

On my SH7709S board, after switching to console(SCI), output is not correct.
Linefeed code output twice, and the first character of the next line is
not seen.

Like follows.
--- console output ----
SuperH SCI(F) driver initialized
sh-sci: ttySC0 at MMIO 0xfffffe80 (irq = 25) is a sci
console handover: boot [bios0] -> real [ttySC0]

h-sci: ttySC1 at MMIO 0xa4000150 (irq = 59) is a scif

h-sci: ttySC2 at MMIO 0xa4000140 (irq = 55) is a irda

oop: module loaded
---------------------------
Atfer applying the patch, I got normal output.

According to sh7709s hardware manual, SCI tx flow-chart says
(1) wait until TDRE=1
(2) write data to TDR
(3) clear TDRE

Why did you changed the sequence ?

SUGIOKA Toshinobu