On Tue, 12 May 2009, Deepak Saxena wrote: > > Commit b5b82df6, from May 2007, breaks no_console_suspend on the OLPC > XO laptop. Basically what happens is that upon returning from resume, > serial8250_resume_port() will reconfigure the port for high speed > mode and all console output will be garbled, making debug of the > resume path painful. This patch modifies serial8250_resume_port() to > not touch the port in the case where it is the console port and console > suspend is disabled. > > Signed-off-by: Deepak Saxena <dsaxena@xxxxxxxxxx> > > --- > The OLPC tree has been carrying a workaround for about two years but > this patch is not the version we've been using. That one can be > found at http://dev.laptop.org/~dsaxena/patches/console_suspend_old.patch. > I prefer the approach of handling this in the 8250 driver itself. Hmm. I already applied this, but then after looking closer, I undid that. Why? It looks buggy: > - if (up->capabilities & UART_NATSEMI) { > + if ((up->capabilities & UART_NATSEMI) && > + (!uart_console(&up->port) && console_suspend_enabled)) { > unsigned char tmp; Isn't that second test wrong? Should it not be if ((up->capabilities & UART_NATSEMI) && (console_suspend_enabled || !uart_console(&up->port)) { instead? In fact, I'd suggest making a helper function called "do_suspend_uart(up)", something like /* * Suspend the uart port unless it's a console. * * But suspend even consoles if "console_suspend_enabled" * is set. */ static inline int do_suspend_uart(struct uart_port *port) { return console_suspend_enabled || !uart_console(port); } and then make all these things (including the _existing_ cases in uart_suspend_port() use that helper function, rather than writing it out. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
