Date: Thu, 20 Oct 2016 21:10:51 +0100
From: Sean Young <sean@mess.org>
To: Nathan Zimmer <nzimmer@sgi.com>
Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
        gregkh@linuxfoundation.org, alan@linux.intel.com
Subject: Re: console issue since 3.6, console=ttyS1 hangs
Message-ID: <20161020201051.GA29324@gofer.mess.org>
References: <20161017144951.GA235535@stormcage.americas.sgi.com>
 <20161017151906.GA19082@gofer.mess.org>
 <20161017164140.GA35950@stormcage.americas.sgi.com>
 <20161018164004.GA159046@stormcage.americas.sgi.com>
 <20161018180518.GA28700@gofer.mess.org>
 <20161018192930.GA207959@stormcage.americas.sgi.com>
 <20161019090719.GA1764@gofer.mess.org>
 <29b311e3-a26e-81de-82cf-e0a202db6d96@sgi.com>
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On Wed, Oct 19, 2016 at 05:13:41PM -0500, Nathan Zimmer wrote:
> On 10/19/2016 04:07 AM, Sean Young wrote:
> >So with 3.6.0:
> >
> >>[    2.079980] Serial: 8250/16550 driver, 8 ports, IRQ sharing disabled
> >>[    2.100887] serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
> >>[    2.101715] serial 00:04: unable to assign resources
> >>[    2.102174] serial: probe of 00:04 failed with error -16
> >The pnp probe fails for some reason. I don't understand why.
> >
> >With 3.7.0:
> >
> >>[    2.062700] Serial: 8250/16550 driver, 8 ports, IRQ sharing disabled
> >>[    2.063250] serial 00:04: [io  0x02f8-0x02ff]
> >>[    2.063875] serial 00:04: [irq 12]
> >>[    2.064345] serial 00:04: [dma 18446744073709551615 disabled]
> >>[    2.065540] serial 00:04: activated
> >>[    2.086442] 00:04: ttyS1 at I/O 0x2f8 (irq = 12) is a 16550A
> >Now the pnp probe succeeds (with broken irq from pnp).
> >
> >Can you please check if there is a wrong irq configured in the bios setup
> >or if there is a bios update available? I don't know why this worked in
> >the first place.
> 
> Apparently this is the latest bios available for these nodes.
> Also in the bios setup screens I don't see anything for changing irq numbers
> for serial console.
> But this is a cluster so sometimes thing get hidden to keep everything
> uniform as possible.
> 
> If you want to point me to the pnp probe code you would be suspicious of I
> can try to debug and see what is going there.

That would be great, thanks. A good start would be to boot 3.6.0 with 
"loglevel=7 pnp.debug=1" and hopefully that will show why the probe
used to fail.

Also, does the issue still exist with a more contemporary kernel?


Sean