From: Tony Lindgren <tony@atomide.com>
To: Vignesh R <vigneshr@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-omap@vger.kernel.org,
Russell King - ARM Linux <linux@armlinux.org.uk>,
linux-arm-kernel@lists.infradead.org,
linux-serial@vger.kernel.org
Subject: Re: 4.16 OMAP serial transmit corruption?
Date: Tue, 17 Apr 2018 10:31:35 -0700 [thread overview]
Message-ID: <20180417173134.GD5671@atomide.com> (raw)
In-Reply-To: <413b774b-d19f-3221-44d5-7992d3b8757f@ti.com>
* Vignesh R <vigneshr@ti.com> [180417 09:21]:
> On Monday 16 April 2018 09:15 PM, Tony Lindgren wrote:
> > Also, I'm seeing an issue where the UARTs won't idle on init
> > with 8250_omap driver if connected to the wl12xx bluetooth port
> > unless I write some data to the port first. It does not seem
> > to be related to the rts/cts lines being wired as I've tested
> > muxing them out of the way.
>
> If this instance of UART is using DMA then it might be due an errata
> worked around in AM33/AM43/DRA7:
> https://patchwork.kernel.org/patch/6784331/
It sure sounds similar but UART_ERRATA_CLOCK_DISABLE does not
seem to help with the reset. Also disabling DMA does not seem
to help. So far the only way to clear it seems to be to write
a character (TX) on the device. Then things work just fine
even without UART_ERRATA_CLOCK_DISABLE set. I'll try to debug
this more at some point.
Regards,
Tony
WARNING: multiple messages have this Message-ID (diff)
From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: 4.16 OMAP serial transmit corruption?
Date: Tue, 17 Apr 2018 10:31:35 -0700 [thread overview]
Message-ID: <20180417173134.GD5671@atomide.com> (raw)
In-Reply-To: <413b774b-d19f-3221-44d5-7992d3b8757f@ti.com>
* Vignesh R <vigneshr@ti.com> [180417 09:21]:
> On Monday 16 April 2018 09:15 PM, Tony Lindgren wrote:
> > Also, I'm seeing an issue where the UARTs won't idle on init
> > with 8250_omap driver if connected to the wl12xx bluetooth port
> > unless I write some data to the port first. It does not seem
> > to be related to the rts/cts lines being wired as I've tested
> > muxing them out of the way.
>
> If this instance of UART is using DMA then it might be due an errata
> worked around in AM33/AM43/DRA7:
> https://patchwork.kernel.org/patch/6784331/
It sure sounds similar but UART_ERRATA_CLOCK_DISABLE does not
seem to help with the reset. Also disabling DMA does not seem
to help. So far the only way to clear it seems to be to write
a character (TX) on the device. Then things work just fine
even without UART_ERRATA_CLOCK_DISABLE set. I'll try to debug
this more at some point.
Regards,
Tony
next prev parent reply other threads:[~2018-04-17 17:31 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-16 15:17 4.16 OMAP serial transmit corruption? Russell King - ARM Linux
2018-04-16 15:17 ` Russell King - ARM Linux
2018-04-16 15:45 ` Tony Lindgren
2018-04-16 15:45 ` Tony Lindgren
2018-04-16 21:26 ` Tony Lindgren
2018-04-16 21:26 ` Tony Lindgren
2018-04-16 23:01 ` Russell King - ARM Linux
2018-04-16 23:01 ` Russell King - ARM Linux
2018-04-17 9:20 ` Vignesh R
2018-04-17 9:20 ` Vignesh R
2018-04-17 17:31 ` Tony Lindgren [this message]
2018-04-17 17:31 ` Tony Lindgren
2018-04-17 22:10 ` Russell King - ARM Linux
2018-04-17 22:10 ` Russell King - ARM Linux
2018-04-18 0:57 ` Tony Lindgren
2018-04-18 0:57 ` Tony Lindgren
2018-04-18 8:18 ` Russell King - ARM Linux
2018-04-18 8:18 ` Russell King - ARM Linux
2018-04-18 9:11 ` Vignesh R
2018-04-18 9:11 ` Vignesh R
2018-04-18 9:59 ` Russell King - ARM Linux
2018-04-18 9:59 ` Russell King - ARM Linux
2018-04-18 10:27 ` Michael Nazzareno Trimarchi
2018-04-18 10:27 ` Michael Nazzareno Trimarchi
2018-04-18 11:00 ` Russell King - ARM Linux
2018-04-18 11:00 ` Russell King - ARM Linux
2018-04-18 11:45 ` Michael Nazzareno Trimarchi
2018-04-18 11:45 ` Michael Nazzareno Trimarchi
2018-04-18 12:17 ` Russell King - ARM Linux
2018-04-18 12:17 ` Russell King - ARM Linux
2018-04-18 12:47 ` Russell King - ARM Linux
2018-04-18 12:47 ` Russell King - ARM Linux
2018-04-16 15:52 ` Tony Lindgren
2018-04-16 15:52 ` Tony Lindgren
2018-04-16 17:48 ` Russell King - ARM Linux
2018-04-16 17:48 ` Russell King - ARM Linux
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