On 06/09/2014 04:59 PM, Aaro Koskinen wrote:> Hi, > > While testing the final 3.15, I noticed the serial console (sunsab) > does not work anymore on Sun Ultra. > > It will tx fine the console output during the boot. But then I try > to type something e.g. at the login: prompt, it behaves oddly: > it re-transmits some old output, and then stalls for a few secs, usually > for each character. Typed characters are however received correctly. > But the console is impossible to use... > > I bisected this to: > > 717f3bbab3c7628736ef738fdbf3d9a28578c26c is the first bad commit > commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c > Author: Seth Bollinger <sethb@xxxxxxxx> > Date: Tue Mar 25 12:55:37 2014 -0500 > > serial_core: Fix conditional start_tx on ring buffer not empty [Let's try that again. This time without the mess] Thanks for the report Aaro. Looks like Seth's fix exposes some broken assumptions in the Sun serial drivers. Can you test the patch below? Regards, Peter Hurley PS - Do you have a way to test also your setup using hardware flow control, ie. CRTSCTS? I ask because I would expect that to be broken even before Seth's patch. --- %< --- From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> Date: Mon, 9 Jun 2014 19:21:43 -0400 Subject: [PATCH] serial: sunsab: Test for no tx data on tx restart Commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c, 'serial_core: Fix conditional start_tx on ring buffer not empty' exposes an incorrect assumption in sunsab's start_tx method; the tx ring buffer can, in fact, be empty when restarting tx when performing flow control. Test for empty tx ring buffer when in sunsab's start_tx method. Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/sunsab.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/sunsab.c b/drivers/tty/serial/sunsab.c index 5faa8e9..b99a4ea 100644 --- a/drivers/tty/serial/sunsab.c +++ b/drivers/tty/serial/sunsab.c @@ -427,6 +427,9 @@ static void sunsab_start_tx(struct uart_port *port) struct circ_buf *xmit = &up->port.state->xmit; int i; + if (uart_circ_empty(xmit)) + return; + up->interrupt_mask1 &= ~(SAB82532_IMR1_ALLS|SAB82532_IMR1_XPR); writeb(up->interrupt_mask1, &up->regs->w.imr1); -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
