On Thu, 2 Feb 2023, Uwe Kleine-König wrote:

> The relevant history introducing serial_lsr_in() looks as follows:
> 
> 	$ git log --graph --oneline --boundary 9fafe733514b..df36f3e3fbb7 -- drivers/tty/serial/8250/8250_port.c
> 	*   df36f3e3fbb7 Merge tag 'v5.19-rc3' into tty-next
> 	|\
> 	| * be03b0651ffd serial: 8250: Store to lsr_save_flags after lsr read
> 	* | ...
> 	* | bdb70c424df1 serial: 8250: Create serial_lsr_in()
> 	* | ce338e4477cf serial: 8250: Store to lsr_save_flags after lsr read
> 	* | ...
> 	|/
> 	o 9fafe733514b tty: remove CMSPAR ifdefs
> 
> So the patch "serial: 8250: Store to lsr_save_flags after lsr read" was
> introduced twice and in one branch it was followed up by commit
> bdb70c424df1 ("serial: 8250: Create serial_lsr_in()") which moved
> explicit lsr_saved_flags handling into a new function serial_lsr_in().
> When the two branches were merged in commit df36f3e3fbb7, we got both,
> serial_lsr_in() and the explicit lsr_saved_flags handling.
> 
> So drop the explicit lsr_saved_flags handling.
> 
> Fixes: df36f3e3fbb7 ("Merge tag 'v5.19-rc3' into tty-next")
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/tty/serial/8250/8250_port.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index 33be7aad11ef..e61753c295d5 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -1512,8 +1512,6 @@ static inline void __stop_tx(struct uart_8250_port *p)
>  		u16 lsr = serial_lsr_in(p);
>  		u64 stop_delay = 0;
>  
> -		p->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
> -
>  		if (!(lsr & UART_LSR_THRE))
>  			return;
>  		/*

I don't know if Fixes tag is appropriate here. This fixes the mismerge 
yes, however, the removed line itself seems harmless so there's no real 
problem to fix.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

-- 
 i.