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Subject: Re: [PATCH net 1/2] r8152: fix the sw rx checksum is unavailable
To: David Miller <davem@davemloft.net>
References: <0835B3720019904CB8F7AA43166CEEB201055ED8@RTITMBSV03.realtek.com.tw>
 <20161124.112152.692025478489876693.davem@davemloft.net>
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 <c3ca9e10-64de-2454-b99a-19e8302f5c12@pobox.com>
Cc: hayeswang@realtek.com, netdev@vger.kernel.org, nic_swsd@realtek.com,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
From: Mark Lord <mlord@pobox.com>
Message-ID: <07a78491-3523-99fd-f08c-10ce277a1793@pobox.com>
Date: Thu, 24 Nov 2016 13:49:48 -0500
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On 16-11-24 01:34 PM, Mark Lord wrote:
>From tracing through the powerpc arch code, this is the buffer that
> is being directly DMA'd into.  And the USB layer does an invalidate_dcache
> on that entire buffer before initiating the DMA (confirmed via printk).

Slight correction:  the invalidate_dcache_range() is only done when
using kmalloc'd buffers.  I have converted the driver here
to use usb_alloc_coherent() instead, so that now gets skipped
since the memory is never cached.