Date: Tue, 21 Jul 2015 19:13:37 +0100 From: Paul Macdonald <paul@ifdnrg.com> To: freebsd-questions@freebsd.org Subject: Re: r220's with serial Message-ID: <55AE8BD1.2020707@ifdnrg.com> In-Reply-To: <55773D18.3060804@ifdnrg.com> References: <55773D18.3060804@ifdnrg.com>
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On 09/06/2015 20:23, Paul Macdonald wrote:
>
> has anyone managed to get serial console access working under dell
> r220's.
>
This was due to an ACPI bug in r220's
Marcel Moolenaar provided me with a fix which is:
-BIOS-
Serial Communication <On with Console Redirection via COM2>
Serial Port Address <Serial Device1=COM2,Serial Device2=COM1>
External Serial Connector <Serial Device 1>
-FreeBSD-
adding the following line to /boot/loader.conf:
hw.uart.console="io:0x2f8,br:57600"
.....
From the looks of it, you have a BIOS bug. In particular a bug in the
ACPI AML (you can dump the ACPI AML with acpidump -d). If I understand
it correctly then the first 2 serial devices (UAR1 and UAR2) have the
same H/W registers. What this boils down to is that the kernel only
works with 1 serial port (UAR1), which ends up having the H/W
configuration of the second serial port (UAR2).
With the BIOS redirecting to COM1 (which is H/W address 0x3f8) and
serial device 1 assigned to COM1 *and* serial device assigned to the
serial port on the chassis, the kernel had no chance to present a login
prompt.
I worked around the problem by reconfiguring the BIOS so that COM2
(which is H/W address 0x2f8) is assigned to serial port 1 and the BIOS
redirecting to COM2. What this does is have COM2 connected to the serial
port on the chassis.
So, even though I suspect that the kernel thinks it’s talking to the
first serial port, it’s actually talking to the second serial port (due
to the ACPI/BIOS bus).
>
>
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