linux-kernel - Re: [PATCH] fix i810 i2c bug

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] [day] [month] [year] [list]

Message-ID: <20110106065329.GF15340@linux-sh.org>
Date:	Thu, 6 Jan 2011 15:53:29 +0900
From:	Paul Mundt <lethal@...ux-sh.org>
To:	Stefani Seibold <stefani@...bold.net>
Cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	linux-fbdev@...r.kernel.org, adaplas@...il.com,
	Maik Broemme <mbroemme@...sserver.de>,
	Dave Airlie <airlied@...ux.ie>
Subject: Re: [PATCH] fix i810 i2c bug

On Mon, Jan 03, 2011 at 10:28:59AM +0100, Stefani Seibold wrote:
> These patch fix a longstanding bug in the i810 frame buffer driver. 
> 
> The handling of the i2c bus is wrong: A 1 bit should not written to the
> i2c, these will be done by switch the i2c to input. Driving an 1 bit
> active is against the i2c spec.
> 
> An active driven of a 1 bit will result in very strange error, depending
> which side is the more powerful one. In my case it depends on the
> temperature of the Display-Controller-EEprom: With an cold eprom a got
> the correct EDID datas, with a warm one some of the 1 bits was 0 :-(
> 
> The same bug is also in the intelfb driver in the file
> drivers/video/intelfb/intelfb_i2c.c. The functions intelfb_gpio_setscl()
> and intelfb_gpio_setsda() do drive the 1 bit active to the i2c bus. But
> since i have no card which is used by the intelfb driver i cannot fix
> it.
> 
> The patch is against linux next-20101231
> 
> - Stefani
> 
> Signed-off-by: Stefani Seibold <stefani@...bold.net>

Applied, thanks.

Also adding intelfb people to the Cc so they're aware of the problem, and
can follow suit.
--
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/