From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH/RFC net-next 3/5] ravb: do not write 1 to reserved bits
Date: Tue, 17 Apr 2018 10:15:53 -0400 (EDT)
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From: Simon Horman <horms+renesas@verge.net.au>
Date: Tue, 17 Apr 2018 10:50:28 +0200

> From: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
> 
> This patch corrects writing 1 to reserved bits.
> The write value should be 0.
> 
> Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

How are we ending up in situations where the driver is trying to write
non-zero values to those fields in the first place?

The places creating those values should be making sure that the
reserved bits are never set.

If you mask out the reserved bits in the register writing locations,
this just hides bugs.