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Date: Thu, 18 Apr 2013 13:15:27 +0200
From: Stephan von Krawczynski <skraw@ithnet.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Bjorn Helgaas <bhelgaas@google.com>, Josh Boyer <jwboyer@gmail.com>,
        richard -rw- weinberger <richard.weinberger@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>
Subject: Re: No serial since kernel 3.8
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On Wed, 17 Apr 2013 20:55:04 +0200
"Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> On Wednesday, April 17, 2013 11:38:30 AM Bjorn Helgaas wrote:
> > [+cc Rafael & linux-acpi]
> 
> Thanks.
> 
> > On Tue, Apr 16, 2013 at 10:14 AM, Stephan von Krawczynski
> > <skraw@ithnet.com> wrote:
> > > On Tue, 16 Apr 2013 10:59:53 -0400
> > > Josh Boyer <jwboyer@gmail.com> wrote:
> > >
> > >> On Tue, Apr 16, 2013 at 04:55:25PM +0200, richard -rw- weinberger wrote:
> > >> >On Tue, Apr 16, 2013 at 4:20 PM, Stephan von Krawczynski
> > >> ><skraw@ithnet.com> wrote:
> > >> >> Hello,
> > >> >>
> > >> >> can some kind soul please explain how I can get my serial port back under
> > >> >> kernel 3.8.X. Earlier kernels showed:
> > >> >>
> > >> >> Jan 10 13:57:18 mybox kernel: [    0.712829] serial8250: ttyS0 at I/O 0x3f8
> > >> >> (irq = 4) is a 16550A
> > >> >>
> > >> >> But 3.8.4:
> > >> >>
> > >> >> Mar 26 10:39:14 admin kernel: [    0.603647] serial 00:0a: disabled
> > >> >>
> > >> >> Only kernel is replaced, no change in distro
> > >> >> Is there some kernel boot parameter needed now?
> > >> >> I tried 3.4.X and it works, even 3.7.X works...
> > >> >
> > >> >So, 3.8.3 worked and 3.8.4 introduced a regression?
> > >> >If so please confirm.
> > >> >
> > >> >CC'ing gregkh, just in case...
> > >>
> > >> We had a report of this in Fedora that was fixed with 3.8.7.  An upstream
> > >> change had been brought back to the 3.8.x series, and it was subsequently
> > >> reverted.  3.8.7 picked up the revert.
> > >>
> > >> josh
> > >
> > > 3.8.7 does not work either. I just checked it. I tried shared and not shared IRQ:
> > >
> > > Apr 16 17:47:05 mybox kernel: [    0.604826] Serial: 8250/16550 driver, 8 ports, IRQ sharing disabled
> > >
> > > and another test:
> > >
> > > Apr 16 18:07:08 mybox kernel: [    0.601203] Serial: 8250/16550 driver, 8 ports, IRQ sharing enabled
> > >
> > > I must say that 3.8.7 does not even tell the "serial 00:0a: disabled" any more.
> > > This is no special board, it is a pretty mainstream asus xeon board with onboard serial.
> > > Loading 3.4.24 (just an example) makes the port work immediately.
> > > Anything else I can test?
> > 
> > 3.7.6 works, and 3.8.3, 3.8.4, 3.8.7 all fail.  So it looks like a
> > regression between 3.7.6 and 3.8.3.
> > 
> > The "serial 00:0a: disabled" message is from PNP, so I added Rafael
> > and linux-acpi.  Complete dmesg logs from 3.7.6 and 3.8.4 would be a
> > place to start.  Also maybe an acpidump, since the 00:0a PNP device
> > probably came from PNPACPI.  You could attach all these to a
> > https://bugzilla.kernel.org report if you want a place to stash them.
> > 
> > Josh, do you have a pointer (URL) to the Fedora issue so we can rule
> > that in or out?
> 
> Stephan, below is a list of commits touching the PNP code between 3.7 and 3.8.
> 
> Can you please check if any of them has triggered the problem you're seeing?
> 
> Rafael
> 
> 
> 13cde3b PNP: Handle IORESOURCE_BITS in resource allocation
> c937766 PNP: Simplify setting of resources
> cdc87c5 pnpacpi: fix incorrect TEST_ALPHA() test
> a6b5e88 ACPI / PNP: Do not crash due to stale pointer use during system resume
> 38de279 pnpbios: remove CONFIG_HOTPLUG ifdefs
> 2905875 ACPI / PNP: skip ACPI device nodes associated with physical nodes already
> 046d9ce ACPI: Move device resources interpretation code from PNP to ACPI core
> 
> -- 
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.

Hello all,

I checked 3.8.8 today and it _does_ work.
Shall we burn some time to find out why?
The only significant output difference between working and not working we could find is:

not working:
Apr  2 17:28:23 mybox kernel: [    0.603270] serial 00:0a: disabled

working (3.8.8):
Apr 18 12:58:50 mybox kernel: [    2.855929] 00:0a: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

-- 
Regards,
Stephan
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