Bug 56721

Summary:	Parport driver uses FIFO even if DMA is disabled in BIOS
Product:	Drivers	Reporter:	Pavel Šefránek (pavel)
Component:	Parallel	Assignee:	drivers_parallel
Status:	NEW ---
Severity:	high	CC:	szg00000
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	3.8.0.18.34	Subsystem:
Regression:	No	Bisected commit-id:

Description Pavel Šefránek 2013-04-17 11:09:04 UTC

If CONFIG_PARPORT_PC_FIFO is set to "y" parport driver is using FIFO everytime despite DMA is disabled in BIOS. This causes slow/stuttering printing through parallel port. 

When I turn DMA on or set CONFIG_PARPORT_PC_FIFO to "n" printer works as expected.

Comment 1 Pavel Šefránek 2013-05-31 09:04:36 UTC

Related Ubuntu bug with more info: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/339752