Re: Re: Re: [PATCH v6 11/13] serial: 8250_dw: add Ambarella CV75 quirks

[Andy Shevchenko]

On Thu, Sep 10, 2026 at 05:45:36PM +0800, zl020895 wrote:
> Hi Ilpo, Andy,
> 
> I'll go with the simple comment:
> 	/*
> 	 * Ambarella keeps variant IER bits (e.g. ETOI) set for correct RX
> 	 * timeout behaviour.
> 	 */
> 	up->ier |= d->pdata->ier_mask;


Works for me.

> At 2026-09-10 17:33:38, "Ilpo Järvinen" <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote:
> >On Thu, 10 Sep 2026, Andy Shevchenko wrote:
> >> On Thu, Sep 10, 2026 at 05:12:52PM +0800, zl020895 wrote:
> >> 
> >> > > Wondering if we should undo this in the port's .shutdown() callback.
> >> > I saw the shutdown path already covers it: dw8250_shutdown() calls
> >> > serial8250_do_shutdown(), which does
> >> > 	up->ier = 0;
> >> > 	serial_port_out(port, UART_IER, 0);
> >> > so both the IER shadow and hardware IER are cleared, including ETOI.
> >> 
> >> Depending on the answer to Ilpo the enabling may need an updated comment
> >> summarising the above.
> >
> >I'd prefer removing the entire "Force them ..." sentence, it feels really 
> >basic detail about how ->ier works. I believe that would resolve your 
> >concern if relates to what shutdown does for the flag (clears it while 
> >the comment as is says nothing is supposed to clear it).
> >
> >> > At 2026-09-10 16:33:14, "Andy Shevchenko" <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> >> > >On Fri, Sep 04, 2026 at 02:38:18PM +0800, Long Zhao via B4 Relay wrote:

...

> >> > >> +	/*
> >> > >> +	 * Ambarella keeps variant IER bits (e.g. ETOI) set for correct RX
> >> > >> +	 * timeout behaviour. Force them into the 8250 IER shadow so later
> >> > >> +	 * generic IER updates do not clear them.
> >> > >> +	 */
> >> > >
> >> > >Wondering if we should undo this in the port's .shutdown() callback.

-- 
With Best Regards,
Andy Shevchenko