Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 27 Sep 2021 16:05:47 +0200
From:   Johan Hovold <johan@kernel.org>
To:     Tony Lindgren <tony@atomide.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andy Shevchenko <andriy.shevchenko@intel.com>,
        Jiri Slaby <jirislaby@kernel.org>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-serial@vger.kernel.org, linux-omap@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/6] serial: core: Add new prep_tx for power management
Message-ID: <YVHPu7KGYDWOCav9@hovoldconsulting.com>
References: <20210921103346.64824-1-tony@atomide.com>
 <20210921103346.64824-4-tony@atomide.com>
 <YUx3AkT4Du/PT+V5@hovoldconsulting.com>
 <YUyXA5UStMHGQDZZ@atomide.com>
 <YU3isENYUb+aE4qi@hovoldconsulting.com>
 <YU3qHiMNHVz/JX/y@atomide.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <YU3qHiMNHVz/JX/y@atomide.com>
Precedence: bulk

On Fri, Sep 24, 2021 at 06:09:18PM +0300, Tony Lindgren wrote:
> * Johan Hovold <johan@kernel.org> [210924 14:38]:
> > On Thu, Sep 23, 2021 at 06:02:27PM +0300, Tony Lindgren wrote:

> > > > No need to be patching line disciplines for this.
> > > 
> > > Do you see issues with handling the errors in line disciplines?
> > 
> > It's just conceptually wrong to push retrying up the stack, possible all
> > the way to user space in case of non-blocking opens, just because the
> > device isn't already runtime active.
> 
> Yes, I don't see a way around that currently. Maybe if we start making
> use of uart_tx_stopped() or something similar that could be simplified.
> And we'll be still hit these line discipline error handling cases
> anyways depending on how long the serial port wake up takes.

I didn't really look at the ldisc change so not saying it isn't needed
for other reasons such as a full write buffer. But then I'd expect it to
be presented as a bug fix (perhaps it was).

Johan