From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: [PATCH] trm290: do hook dma_host_{on,off} methods (take 2)
Date: Fri, 28 Dec 2007 22:41:26 +0300 [thread overview]
Message-ID: <47755166.7030809@ru.mvista.com> (raw)
In-Reply-To: <200712271705.32867.bzolnier@gmail.com>
Hello.
Bartlomiej Zolnierkiewicz wrote:
>>Using default methods caused the chip's DMA PRD count registers, inadvertently
>>starting DMA! While fixing it, also do:
> nasty, this could possibly explain the following trm290.c hack:
Frankly speaking, I'm not sure it's that destructive: the register in
question is accessed by inw()/outw() while the genric code would only "spoil"
it by inb(). So, I don't know if this would be access to the same register as
outw() does (that write starts DMA, and it is a number of 32-bit words in PRD
table - 1). Actually, the PRD address is loaded by 32-bit write at address 2
bytes below the one in question, and so overlaps our register -- the chip must
be looking at byte enables when deciding what register is addressed).
> ...
> #if 0 /* play it safe for now */
IDE_HFLAG_TRUST_BIOS_FOR_DMA |
> #endif
> ...
>>- get rid of the 'ide_' prefixes in several functions for which the prefix in
>> the method's name has been 'ide_' ectomized already;
>>- align the code hooking the IDE DMA methods in init_hwif_trm290()...
>>---
>>Fixed the header, added 'static' to the new method definitions.
>>The patch is against Linus' kernel tree...
>>Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
> applied
The next patch is cooking... :-)
WBR, Sergei
prev parent reply other threads:[~2007-12-28 19:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-27 10:55 [PATCH] trm290: do hook dma_host_{on,off} methods (take 2) Sergei Shtylyov
2007-12-27 16:05 ` Bartlomiej Zolnierkiewicz
2007-12-28 19:41 ` Sergei Shtylyov [this message]
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