Re: [PATCH] stmmac: explicitly zero des0 & des1 on init

David Miller
2015-06-21T16:18:09Z

From: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Date: Tue, 16 Jun 2015 20:40:41 +0300

> Current implementtion of descriptor init procedure only takes care about
> ownership flag. While it is perfectly possible to have underlying memory
> filled with garbage on boot or driver installation.
>
> And randomly set flags in non-zeroed des0 and des1 fields may lead to
> unpredictable behavior of the GMAC DMA block.
>
> Solution to this problem is as simple as explicit zeroing of both des0
> and des1 fields of all buffer descriptors.
>
> Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

If you need the memory zero initialized, use dma_zalloc_coherent().
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