RE: PATA IDE is slower in newer versions of kernel

[Maxim Levitsky <maximlevitsky@gmail.com>]

On Sat, 2010-09-18 at 11:12 -0600, Joshua Hintze wrote:
> Some updated information. I created a screen capture of what I am seeing. First is the logic analyzer when the newer linux kernel is writing slow to the PATA port.
> 
> http://i56.tinypic.com/oqhrug.png
> 
> Notice in the above link how there is a lot of activating and then large gaps of no activity. After about 9 mS the STOP line is strobed a few times and then DMARQ finally returns to normal operating. The link below shows the picture of an old 2.6.10 kernel where write speeds are much faster.
> 
> http://i51.tinypic.com/a9wiur.png
> 
> In the above image notice how the wait time is considerable less 100's of microseconds before the stop lines get strobed.
> 
> I'm dedicated to continue working on the problem, I just need to advice from the linux community. I've tried different I/O schedulers such as noop and anticipatory and I'm studying the ide-dma code but still lost to where this is happening.
> 
> Thanks!
> 
Maybe you can just bisect this?
Just a general advice, I don't know ide subsystem at all.

Best regards,
	Maxim Levitsky