From: ael <law_ence.dev@ntlworld.com>
To: linux-serial@vger.kernel.org
Subject: Regression: 8250 with 2.6.24
Date: Fri, 08 Feb 2008 18:29:08 +0000 [thread overview]
Message-ID: <foi71k$pem$1@ger.gmane.org> (raw)
Legacy i386 system with Intel 440BX chip set:
------------------------------------------------------------------------
# lspci
00:00.0 Host bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX Host
bridge (rev 02)
00:01.0 PCI bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX AGP
bridge (rev 02)
00:07.0 ISA bridge: Intel Corporation 82371AB/EB/MB PIIX4 ISA (rev 02)
00:07.1 IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)
00:07.2 USB Controller: Intel Corporation 82371AB/EB/MB PIIX4 USB (rev 01)
00:07.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 02)
00:08.0 SCSI storage controller: Adaptec AHA-2940U/UW/D / AIC-7881U (rev 01)
00:0a.0 Ethernet controller: Lite-On Communications Inc LNE100TX (rev 20)
01:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200 AGP
(rev 01)
----------------------------------------------------------------------
Moving from 2.6.23.14 to 2.6.24, the /dev/ttyS* are incorrectly created:-
In /var/log/messages:-
----------------------------------------------------------------------
Feb 4 17:01:54 conquest3 kernel: serial8250: ttyS0 at I/O 0x3f8 (irq =
4) is a 16550A
Feb 4 17:01:54 conquest3 kernel: serial8250: ttyS1 at I/O 0x2f8 (irq =
3) is a 16550A
Feb 4 17:01:54 conquest3 kernel: 00:0c: ttyS0 at I/O 0x3f8 (irq = 4) is
a 16550A
Feb 4 17:01:54 conquest3 kernel: 00:0f: ttyS1 at I/O 0x2f8 (irq = 3) is
a 16550A
------------------------------------------------------------------------
[which is correct.]
However:-
# ls -l /sys/devices/platform/serial8250/tty/
total 0
drwxr-xr-x 3 root root 0 Feb 8 18:22 ttyS2
drwxr-xr-x 3 root root 0 Feb 8 18:22 ttyS3
[which is incorrect.]
udev then creates the wrong devices:-
# ls -l /dev/ttyS*
crw-rw---- 1 root dialout 4, 66 Feb 8 18:03 /dev/ttyS2
crw-rw---- 1 root dialout 4, 67 Feb 8 18:03 /dev/ttyS3
Accessing those nodes gives errors:
# statserial /dev/ttyS3
statserial: TIOCMGET failed: Input/output error
Complications:
--------------
1) This is non deterministic: very rarely all four devices appear:
ttyS0,ttyS1, ttyS2 and ttyS3. Accessing ttyS0 and ttys1 then works
correctly.
2) 2.6.23.14 (and probably earlier kernels) also generated 4 devices,
and rarely had a similar problem - but I can't recall exact details.
Thus the bug might have been around for a longish period with some sort
of race triggered almost always in 2.6.24.
-------------------------------------------------------------------------
Anyone throw any light on this?
ael
next reply other threads:[~2008-02-08 22:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-08 18:29 ael [this message]
2008-02-15 20:40 ` Regression: 8250 with 2.6.24 ael
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