linux-kernel - Re: [PATCH RFC] x86: Fix 64-bit DMA masks on VIA

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20080424153240.33b5300c@the-village.bc.nu>
Date:	Thu, 24 Apr 2008 15:32:40 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Michael Buesch <mb@...sch.de>
Cc:	Andi Kleen <andi@...stfloor.org>,
	"linux-kernel" <linux-kernel@...r.kernel.org>, vojtech@...e.cz,
	muli@...ibm.com, jdmason@...zu.us, tglx@...utronix.de,
	mingo@...hat.com
Subject: Re: [PATCH RFC] x86: Fix 64-bit DMA masks on VIA

On Thu, 24 Apr 2008 16:06:00 +0200
Michael Buesch <mb@...sch.de> wrote:

> On Thursday 24 April 2008 15:43:50 Andi Kleen wrote:
> > Michael Buesch <mb@...sch.de> writes:
> > 
> > > This untested patch is supposed to fix DMAing on some VIA boards.
> > > Currently the DMA subsystem returns an error, if the driver does
> > > tell that it supports a 64bit DMA mask. So the driver probing
> > > would fail in that case. 
> > 
> > The driver is broken then. It is supposed to retry with a small
> > mask on an error. Please fix the driver.
> 
> I already added a workaround to the driver.
> Why do we need to workaround this in _every_ driver? (Note that _every_
> driver supporting a 64bit mask is affected). Why not fix it in the DMA layer?

Some hardware wants to know it can get a given DMA mask or failure. I
agree however that a "pci_prefer_64bit_dma(pdev)" function would be a
good patch for someone to submit tot he PCI layer code.

Alan
--
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/