From: "Antonino A. Daplas" <adaplas@pol.net>
To: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Jean Delvare <khali@linux-fr.org>, Andrew Morton <akpm@osdl.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] cirrus-logic-framebuffer-i2c-support.patch
Date: Mon, 10 Jul 2006 23:18:45 +0800 [thread overview]
Message-ID: <44B26FD5.403@pol.net> (raw)
In-Reply-To: <m3u05p4mkx.fsf@defiant.localdomain>
Krzysztof Halasa wrote:
> "Antonino A. Daplas" <adaplas@pol.net> writes:
>
>> Eventually, I'm the one who's going to maintain the code, most
>> of the drivers in the video directory are practically abandoned.
>
> BTW, it's fortunate that you are maintaing it. The I2C code in cirrusfb
> uses vga_wseq() and vga_rseq(). Is it safe WRT races between I2C
> adapter code and fb code? I don't see any locking here, and both
> functions are non-atomic (write merging and posting will not break it,
> but it looks like I need a lock for concurent access).
Correcting myself: vga_wseq() is not a problem in little endian machines
because the 2 single-byte writes are done with a single 2-byte write.
vga_rseq() is not safe though.
I don't know how big a problem this is, reading the i2c bus while the
video mode is changing..., but I agree that it might be worthwhile
to at least lock sequencer access.
Tony
prev parent reply other threads:[~2006-07-10 15:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200607050147.k651kxmT023763@shell0.pdx.osdl.net>
[not found] ` <20060705165255.ab7f1b83.khali@linux-fr.org>
2006-07-09 20:37 ` [PATCH v2] cirrus-logic-framebuffer-i2c-support.patch Krzysztof Halasa
2006-07-09 23:53 ` Antonino A. Daplas
2006-07-10 9:49 ` Krzysztof Halasa
2006-07-10 10:07 ` Antonino A. Daplas
2006-07-10 10:49 ` Krzysztof Halasa
2006-07-10 11:27 ` Antonino A. Daplas
2006-07-10 11:49 ` Krzysztof Halasa
2006-07-10 12:32 ` Antonino A. Daplas
2006-07-10 13:09 ` Krzysztof Halasa
2006-07-10 14:29 ` Antonino A. Daplas
2006-07-10 14:46 ` Krzysztof Halasa
2006-07-27 21:23 ` Jean Delvare
2006-07-10 13:27 ` Krzysztof Halasa
2006-07-10 14:11 ` Antonino A. Daplas
2006-07-10 15:37 ` Krzysztof Halasa
2006-07-10 16:30 ` Antonino A. Daplas
2006-07-10 20:34 ` Krzysztof Halasa
2006-07-11 7:22 ` Antonino A. Daplas
2006-07-11 10:53 ` Krzysztof Halasa
2006-07-27 20:55 ` Jean Delvare
2006-07-28 10:05 ` Krzysztof Halasa
2006-07-10 15:18 ` Antonino A. Daplas [this message]
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