linux-kernel - Re: [PATCH] tty: serial: fixed uart irq maybe cause irq storm

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Message-ID: <7dd8f053-aaba-beaa-0f2f-118b0b1c2d85@linux.intel.com>
Date: Tue, 2 Apr 2024 14:38:48 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Feng Chunguo <chunguo.feng@...idrive.com>
cc: Greg KH <gregkh@...uxfoundation.org>, 
    "fengchunguo@....com" <fengchunguo@....com>, 
    Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
    Jiri Slaby <jirislaby@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] tty: serial: fixed uart irq maybe cause irq storm

On Mon, 1 Apr 2024, Feng Chunguo wrote:

> Hi Greg KH，
> 
> Sent this path again.
> 
>  the irq should not be turned off here, what happens if some data comes in while this
> function is running?  Will it be lost?
> --> lost，not receive other irq.
> 
>  When the uart was switching the baud rate from one to other,  this issue can be
> reproduced.


>> This feels wrong,
>> the irq should not be turned off here, what happens if some data comes in while this
>> function is running? Will it be lost? thanks, greg k-h

Changing rate always risks losing what's currently on wire due to timing 
related corruption, I don't think there there's a way around that IRQ 
being enabled or not.


-- 
 i.