Stefan Wahren <stefan.wahren@xxxxxxxx> writes: > Hi, > > Am 25.03.23 um 16:11 schrieb Uwe Kleine-König: [...] > today i had time to do some testing. At first i tested with different RXTL_DEFAULT values. > > 1 No overrun > 2 No overrun > 4 No overrun > 8 Overruns > > After that i look at the # echo 0 > /proc/sys/kernel/printk approach, > but this didn't change anything. The kernel is usually silent about > log message after boot and the console works still with echo. > Enforcing some driver to call printk periodically would make the > console unusuable. As you figured that printk() is not the cause, it must be something else that causes overruns, so there is no need to check printk case further. > > Finally i tried to disabled the spin_lock in imx_uart_console_write: > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > index f07c4f9ff13c..c342559ff1a2 100644 > --- a/drivers/tty/serial/imx.c > +++ b/drivers/tty/serial/imx.c > @@ -2007,14 +2007,12 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) > struct imx_port_ucrs old_ucr; > unsigned long flags; > unsigned int ucr1; > - int locked = 1; > + int locked = 0; > > if (sport->port.sysrq) > locked = 0; > else if (oops_in_progress) > locked = spin_trylock_irqsave(&sport->port.lock, flags); > - else > - spin_lock_irqsave(&sport->port.lock, flags); > > /* > * First, save UCR1/2/3 and then disable interrupts > > But the overruns still occured. Is this because the serial core > already helds a lock? This probably isn't even called when there is no printk() output, as user-space writes to /dev/console are rather performed through regular generic code, AFAIK. Best regards, -- Sergey Organov
