From: Felix Fietkau <nbd@openwrt.org>
To: tom.leiming@gmail.com
Cc: lrodriguez@atheros.com, linux-wireless@vger.kernel.org,
linville@tuxdriver.com
Subject: Re: [PATCH 2/2] ath9k: fix dma sync in rx path
Date: Fri, 14 May 2010 16:28:24 +0200 [thread overview]
Message-ID: <4BED5E08.3050000@openwrt.org> (raw)
In-Reply-To: <1273842969-3435-1-git-send-email-tom.leiming@gmail.com>
On 2010-05-14 3:16 PM, tom.leiming@gmail.com wrote:
> From: Ming Lei <tom.leiming@gmail.com>
>
> If buffer is to be accessed by cpu after dma transfer is over, but
> between dma mapping and dma unmapping, we should use
> dma_sync_single_for_cpu to sync the buffer between cpu with
> device. And dma_sync_single_for_device is used to let
> device gain the buffer again.
I think this patch is wrong. On most MIPS devices,
dma_sync_single_for_cpu is a no-op. In fact, with this patch, the rx
path fails very quickly.
I believe keeping the dma_sync_single_for_device variant is necessary
for all syncs.
- Felix
next prev parent reply other threads:[~2010-05-14 14:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-14 13:15 [PATCH 1/2] ath9k: fix dma direction for map/unmap in ath_rx_tasklet tom.leiming
2010-05-14 13:16 ` [PATCH 2/2] ath9k: fix dma sync in rx path tom.leiming
2010-05-14 14:28 ` Felix Fietkau [this message]
2010-05-14 15:27 ` Ming Lei
2010-05-14 16:19 ` Felix Fietkau
2010-05-15 1:31 ` Ming Lei
2010-05-15 9:25 ` Felix Fietkau
2010-05-15 9:52 ` Ming Lei
2010-05-15 10:25 ` Ming Lei
2010-05-15 10:44 ` Felix Fietkau
2010-05-27 13:51 ` Felix Fietkau
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