Bug 56721

Summary: Parport driver uses FIFO even if DMA is disabled in BIOS
Product: Drivers Reporter: Pavel Šefránek (pavel)
Component: ParallelAssignee: drivers_parallel
Status: NEW ---    
Severity: high CC: szg00000
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 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