linux-kernel - Re: dma hardware underrun

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Sun, 22 Jul 2007 15:53:10 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	"treul" <lgijnpuhx@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: dma hardware underrun

> My debugging result shows the underrun goes away if I put 2 printf's in the 
> harddisk ISR. The printf is at milli-seconds whereas the duration of the 
> original ISR is at lower magnitude. In addition, I find a SATA-PCI harddisk 
> does not have the underrun problem. IDE-PCI device gets the trouble.

Is the SATA controller on the motherboard and the PATA one on the PCI
bus ?

> So, do you have any idea about where the root cause can be hiding? Or what 
> do you think of adding printf's in ISR? (performance? incurring other 
> problems by disabling interrupt too long?

On a standard PCI bus an IDE DMA disk can saturate the bus. That may be
your underlying problem ?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/