Messages in this thread Patch in this message | | | From | Kumar Gala <> | Subject | Re: [PATCH] Revert serial 8250 console fixes | Date | Mon, 6 Feb 2006 14:56:46 -0600 |
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On Feb 6, 2006, at 1:38 PM, Alan Cox wrote:
> On Llu, 2006-02-06 at 13:14 -0600, Kumar Gala wrote: >> Can you explain further why you had to change wait_for_xmitr() from >> testing BOTH_EMPTY to UART_LSR_THRE. > > Because you want to wait for the uart to show that it is ready to > accept > a character, not that the byte has been clocked out entirely. Thats > essential for working with virtual serial ports on servers as they use > the fact there is no pending character to work out how to packetize it > as a TCP stream. > > >> Also, what exactly would you be looking for in a register dump? > > When it gets stuck what state are the serial chip registers in and > where > is the OS hanging ?
The following seems to make things better for me. Can you take a look and let me know what you thing. If it looks good, I'll send Russell a clean patch:
- kumar
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 179c1f0..b1fc97d 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -2229,6 +2229,7 @@ serial8250_console_write(struct console * and restore the IER */ wait_for_xmitr(up, BOTH_EMPTY); + up->ier |= UART_IER_THRI; serial_out(up, UART_IER, ier | UART_IER_THRI); }
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