linux-kernel - Re: [PATCH] mmc_spi: fail gracefully if host or card do not support the switch command

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]

Message-ID: <20090615212409.14e7a51b@mjolnir.ossman.eu>
Date:	Mon, 15 Jun 2009 21:24:09 +0200
From:	Pierre Ossman <pierre@...man.eu>
To:	Wolfgang Mües <wolfgang.mues@...rswald.de>
Cc:	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Matt Fleming" <matt@...sole-pimps.org>,
	"David Brownell" <dbrownell@...rs.sourceforge.net>,
	"Mike Frysinger" <vapier.adi@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc_spi: fail gracefully if host or card do not support
 the switch command

On Mon, 15 Jun 2009 10:36:05 +0200
Wolfgang Mües <wolfgang.mues@...rswald.de> wrote:

> Am Samstag, 13. Juni 2009 schrieb Pierre Ossman:
> > For SD there are several checks 
> > before the switch command is actually issued.
> 
> But there are two cases not covered by these checks:
> 
> a) the switch command is supported, but the card is not capable of switching 
> to 50 MHz.
> 

But a successful switch command (even if the response is that the card
cannot do it) should not need the checks you added. The switch data
structure is checked further down.

> b) the card rejects the switch command in SPI mode, because it is not 
> mandatory here.

I cannot see anything in the spec backing up this claim.

Rgds
-- 
     -- Pierre Ossman

  WARNING: This correspondence is being monitored by the
  Swedish government. Make sure your server uses encryption
  for SMTP traffic and consider using PGP for end-to-end
  encryption.

Download attachment "signature.asc" of type "application/pgp-signature" (199 bytes)