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From: Max Filippov <jcmvbkbc@gmail.com>
To: Kalle Valo <kalle.valo@iki.fi>
Cc: linux-wireless@vger.kernel.org, Christian Lamparter <chunkeey@web.de>
Subject: Re: [PATCH 5/5] p54spi: use firmware/DMA bug workaround that work under hight load in p54spi_rx
Date: Tue, 19 May 2009 01:21:13 +0400	[thread overview]
Message-ID: <200905190121.14103.jcmvbkbc@gmail.com> (raw)
In-Reply-To: <87tz3i9ram.fsf@litku.valot.fi>

> Max Filippov <jcmvbkbc@gmail.com> writes:
> > Under high load first data word, read after available data size
> > is sometimes lost in p54spi_rx. It seems to depend on frequency
> > of interrupts and latency of data read request relatively to
> > 'data available' interrupt. The worst consequence of this bug
> > is loss of packet transmission acknowledgement, which in turn
> > causes overflow of tx queues and permanent link loss.
> >
> > Read data size and first data word in one SPI transaction.
> > No packets from LMAC should have length less than 1 word,
> > so this shouldn't interfere with the next read transaction.
>
> There is a bug in omap2_mcspi which corrupts some DMA transfers, I don't
> know if the bug you see is this one or something else. I'll send the
> patch to linux-omap sometime later this week.

I guess it will be easy to check whether your patch changes something in 
original p54spi behavior. I'll test this.

Thanks.
-- Max


      reply	other threads:[~2009-05-18 21:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <0001-p54spi-fix-incorrect-access-sequence-to-DMA_WRITE_C.patch>
2009-05-17 23:02 ` [PATCH 0/5] p54spi: fixes to achieve link stability Max Filippov
2009-05-17 23:02   ` [PATCH 1/5] p54spi: fix incorrect access sequence to DMA_WRITE_CTRL in p54spi_spi_write_dma Max Filippov
2009-05-17 23:02     ` [PATCH 2/5] p54spi: cosmetic fixes: use even byte count in SPI write; drop unused interrupt status read Max Filippov
2009-05-17 23:02       ` [PATCH 3/5] p54spi: return status of p54spi_wakeup Max Filippov
2009-05-17 23:02         ` [PATCH 4/5] p54spi: always call p54spi_sleep in p54spi_tx_frame if p54spi_wakeup succeeded Max Filippov
2009-05-17 23:02           ` [PATCH 5/5] p54spi: use firmware/DMA bug workaround that work under hight load in p54spi_rx Max Filippov
2009-05-18 18:53             ` Kalle Valo
2009-05-18 21:21               ` Max Filippov [this message]

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