From: Tony Lindgren <tony@atomide.com>
To: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andy Shevchenko <andriy.shevchenko@intel.com>,
Jiri Slaby <jirislaby@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Vignesh Raghavendra <vigneshr@ti.com>,
linux-serial@vger.kernel.org, linux-omap@vger.kernel.org,
linux-kernel@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCHv4 0/7] Serial port generic PM to fix 8250 PM
Date: Thu, 9 Dec 2021 09:37:25 +0200 [thread overview]
Message-ID: <YbGyNW2EQlA/+VIg@atomide.com> (raw)
In-Reply-To: <YaX2mbUv9Yv3icl4@hovoldconsulting.com>
* Johan Hovold <johan@kernel.org> [211130 10:03]:
> Specifically, it looks like tx can still stall indefinitely if the
> autosuspend timer fires. This can happen at low baud rates and also when
> using flow control.
Yeah the TX part is still problematic. Note that this is purely because
of current Linux serial layers implementation, and not because of any
hardware reasons.
Even after this series we still rely on serial8250_rpm_get_tx() and
serial8250_rpm_put_tx() to decipher if we can idle the port..
If anybody has good ideas where we can add the serial core TX related
paired runtime PM calls please let me know :)
For TX DMA, we should not do runtime PM put until at the DMA callback
function when completed.
Regards,
Tony
prev parent reply other threads:[~2021-12-09 7:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-15 8:41 [PATCHv4 0/7] Serial port generic PM to fix 8250 PM Tony Lindgren
2021-11-15 8:41 ` [PATCH 1/7] serial: core: Add support of runtime PM Tony Lindgren
2021-11-16 7:40 ` kernel test robot
2021-11-30 10:28 ` Johan Hovold
2021-12-09 7:29 ` Tony Lindgren
2021-12-09 10:35 ` Andy Shevchenko
2022-01-18 9:41 ` Tony Lindgren
2022-04-11 10:36 ` Andy Shevchenko
2022-04-11 10:55 ` Tony Lindgren
2021-11-15 8:41 ` [PATCH 2/7] serial: core: Add wakeup() and start_pending_tx() for asynchronous wake Tony Lindgren
2021-11-30 10:34 ` Johan Hovold
2021-11-15 8:41 ` [PATCH 3/7] serial: 8250_port: properly handle runtime PM in IRQ Tony Lindgren
2021-11-30 10:36 ` Johan Hovold
2021-11-15 8:42 ` [PATCH 4/7] serial: 8250: Implement wakeup for TX and use it for 8250_omap Tony Lindgren
2021-11-30 10:38 ` Johan Hovold
2021-11-15 8:42 ` [PATCH 5/7] serial: 8250_omap: Require a valid wakeirq for deeper idle states Tony Lindgren
2021-11-30 10:40 ` Johan Hovold
2021-11-15 8:42 ` [PATCH 6/7] serial: 8250_omap: Drop the use of pm_runtime_irq_safe() Tony Lindgren
2021-11-30 10:42 ` Johan Hovold
2021-11-15 8:42 ` [PATCH 7/7] serial: 8250_port: Remove calls to runtime PM Tony Lindgren
2021-11-30 10:47 ` Johan Hovold
2021-11-26 16:01 ` [PATCHv4 0/7] Serial port generic PM to fix 8250 PM Andy Shevchenko
2021-11-30 10:02 ` Johan Hovold
2021-12-09 7:37 ` Tony Lindgren [this message]
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