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From: Tony Lindgren <tony@atomide.com>
To: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-omap@vger.kernel.org, Vignesh R <vigneshr@ti.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-serial@vger.kernel.org
Subject: Re: 4.16 OMAP serial transmit corruption?
Date: Tue, 17 Apr 2018 17:57:48 -0700	[thread overview]
Message-ID: <20180418005748.GE5671@atomide.com> (raw)
In-Reply-To: <20180417221029.GL10990@n2100.armlinux.org.uk>

* Russell King - ARM Linux <linux@armlinux.org.uk> [180417 22:12]:
> On Tue, Apr 17, 2018 at 10:31:35AM -0700, Tony Lindgren wrote:
> > * 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.
> 
> Classic case of thread hijack.  So, Tony's idle problem gets more
> attention on _my_ thread than _my_ issue about TX corruption, yea,
> that's fair...  Come on guys, what about my problem, which is the
> subject of this thread?

Just trying to brainstorm what all can go wrong still :) OK so
it's not DMA then.

> I don't have CONFIG_SERIAL_8250_DMA set, so DMA can't be the issue.

Is this happening also with v4.16 or with v4.17-rc1?

So you just edit something in vi and and on exit it happens?
Not happening here for me..

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 17:57:48 -0700	[thread overview]
Message-ID: <20180418005748.GE5671@atomide.com> (raw)
In-Reply-To: <20180417221029.GL10990@n2100.armlinux.org.uk>

* Russell King - ARM Linux <linux@armlinux.org.uk> [180417 22:12]:
> On Tue, Apr 17, 2018 at 10:31:35AM -0700, Tony Lindgren wrote:
> > * 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.
> 
> Classic case of thread hijack.  So, Tony's idle problem gets more
> attention on _my_ thread than _my_ issue about TX corruption, yea,
> that's fair...  Come on guys, what about my problem, which is the
> subject of this thread?

Just trying to brainstorm what all can go wrong still :) OK so
it's not DMA then.

> I don't have CONFIG_SERIAL_8250_DMA set, so DMA can't be the issue.

Is this happening also with v4.16 or with v4.17-rc1?

So you just edit something in vi and and on exit it happens?
Not happening here for me..

Regards,

Tony

  reply	other threads:[~2018-04-18  0:57 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
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 [this message]
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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