On Fri, Oct 28, 2016 at 02:42:25PM -0500, Nathan Zimmer wrote:

On Thu, Oct 27, 2016 at 09:19:16PM +0100, Sean Young wrote:

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On Wed, Oct 26, 2016 at 01:16:16PM -0500, Nathan Zimmer wrote:

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On 10/25/2016 03:41 PM, Sean Young wrote:

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On Mon, Oct 24, 2016 at 04:49:25PM -0500, Nathan Zimmer wrote:

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[    1.565062] serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A

The isa probe driver find the serial port.

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[    1.566453] serial 00:04: pnp_assign_resources, try dependent set 0
[    1.567383] serial 00:04:   couldn't assign io 0 (min 0x2f8 max 0x2f8)

But then decides that the port is already in use (the existing serial driver).

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[    1.568366] serial 00:04: pnp_assign_resources failed (-16)
[    1.569188] serial 00:04: unable to assign resources
[    1.569924] serial: probe of 00:04 failed with error -16

Please try and boot 3.7.0 with "8250.share_irqs=1", maybe it will pick
irq 3 and it will be happy again, but that is just a guess.

I think I have not fully understood what the failure is. Does the serial
port not work or does the boot hang? What are the symptoms?

With console=ttyS1 the boot will "hang", sometimes it makes it all the way
through but may take 30 minutes, instead of the 2-4 minutes this box

Where does it hang? Any error messages?

Shortly after mounting the root.
After that I get no more output...

Here is a failure log from 4.8.

So does the console on the serial port work on 4.8? Also what does 
"cat /proc/interrupts" say with and without my change of ordering the
serial pnp probe before the isa probe?

It could be that the serial driver picking a different irq caused another
driver to be forced to pick another irq which does not work.


Sean