Ondřej Jirman <megi@xxxxxx> writes: > On Tue, Apr 04, 2023 at 09:51:11AM +0200, Heiko Stübner wrote: >> Hi, >> >> Am Montag, 3. April 2023, 19:59:37 CEST schrieb Javier Martinez Canillas: >> > This baud rate is set for the device by mainline u-boot and is also what >> > is set in the Pinebook Pro Device Tree, which is a device similar to the >> > PinePhone Pro but with a different form factor. >> > >> > Otherwise, the baud rate of the firmware and Linux don't match by default >> > and a 'console=ttyS2,1500000n8' kernel command line parameter is required >> > to have proper output for both. >> >> The interesting question is always if this will break someone else's setup. >> I've never really understood the strange setting of 1.5MBps, but on the >> other hand it _is_ a reality on most boards. > > Normal users of the phone probably run with UART console disabled, because > UART is muxed with audio jack output and to enable it they have to add > console=ttyS2 to the kernel command line and flip a physical switch inside > the phone. > > Fortunately, not sepcifying stdout-path baud rate in the options part > of the string, will make the serial driver probe for the baud rate from > the previous boot stage and make the user happy by keeping whatever was > already set in the bootloader. > As mentioned in the first email of this thread, I tried that but it didn't work for me. Either using stdout-path = "serial2"; or stdout-path = &uart2; gives me no serial output with console=ttyS2, I needed to specify the baud rate explicitly (i.e: console=ttyS2,1500000n8). > https://elixir.bootlin.com/linux/latest/source/drivers/tty/serial/8250/8250_port.c#L3496 > Is that helper really used by the serial driver in the PinePhone Pro? (drivers/tty/serial/8250/8250_dw.c), I was meaning to dig why just ttyS2 was not working but decided that could be a follow-up patch. Since chaging to 1.5 MBps seemed to have merits on its own, decided to post this patch anyways in the meantime. > So we can make the kernel just keep the baudrate setup from the previous > boot stage by: > > stdout-path = "serial2"; > Did it work for you? Maybe I'm doing something silly but as mentioned it didn't work for me with upstream u-boot. > regards, > o. > -- Best regards, Javier Martinez Canillas Core Platforms Red Hat
