Ubuntu
linux package

  1. Precise (12.04)
  2. Bug #339752
  3. Comment #7

Comment 7 for bug 339752

Revision history for this message
Pavel Šefránek (pavelsefranek) wrote : Re: Slow/stuttering printing through parallel port

Seems I am very close to resolving this bug. I've done some deep testing today under following OSes (all are in the newest version):
1) CentOS 6.3
2) Fedora 17
3) openSUSE 12.2
4) Ubuntu 12.04

Under all 4, there is the same ownership of /dev/lp0 and /dev/parport0 (owner root/group lp, permissions 660), BUT I have found the difference between Red Hat based systems (where the parallel printer works well) and the others (Ubuntu and openSUSE - where id doesn't work well). The output of "dmesg|grep parport" for Red Hat based is:

[ 7.522714] parport_pc 00:06: reported by Plug and Play ACPI
[ 7.522769] parport0: PC-style at 0x278 (0x678), irq 5 [PCSPP,TRISTATE]
[ 45.177790] lp0: using parport0 (interrupt-driven).

however Ubuntu and openSUSE dmesg "dmesg|grep parport" says this:

[ 21.205326] parport_pc 00:06: reported by Plug and Play ACPI
[ 21.205380] parport0: PC-style at 0x278 (0x678), irq 5, using FIFO [PCSPP,TRISTATE,COMPAT,ECP]
[ 21.326415] lp0: using parport0 (interrupt-driven).

So the diffrence between those two seems to be between enabling and disabling FIFO. I've also looked at kernel configure files for Fedora 17 and Ubuntu 12.04 and I am posting the important section here:

Ubuntu 12.04 kernel configuration file (section PARPORT):
CONFIG_PARPORT=m
CONFIG_PARPORT_PC=m
CONFIG_PARPORT_SERIAL=m
CONFIG_PARPORT_PC_FIFO=y
# CONFIG_PARPORT_PC_SUPERIO is not set
CONFIG_PARPORT_PC_PCMCIA=m
# CONFIG_PARPORT_GSC is not set
CONFIG_PARPORT_AX88796=m
CONFIG_PARPORT_1284=y
CONFIG_PARPORT_NOT_PC=y

Fedora 17 kernel configuration file (section PARPORT):
# Parallel port support
#
CONFIG_PARPORT=m
CONFIG_PARPORT_PC=m
CONFIG_PARPORT_SERIAL=m
# CONFIG_PARPORT_PC_FIFO is not set
# CONFIG_PARPORT_PC_SUPERIO is not set
CONFIG_PARPORT_PC_PCMCIA=m
CONFIG_PARPORT_1284=y
# CONFIG_PARPORT_AX88796 is not set

CONFIG_ACPI_PCI_SLOT=y
CONFIG_HOTPLUG_PCI_ACPI=y
CONFIG_HOTPLUG_PCI_ACPI_IBM=m

I am not so experienced to recompile the kernel with option CONFIG_PARPORT_PC_FIFO=n on my own so by this post I would like to please someone to do this for us. Or please post here a guide how to quickly recompile the kernel with changed parameter CONFIG_PARPORT_PC_FIFO. Many thanks to kernel team!