linux-kernel - vga and 64-bit memcpy's

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Message-ID: <CAPM=9tyZF2S7PJcLyc=KH_NBFXju8UwvMBOF_MocNK8pPVXDYw@mail.gmail.com>
Date:	Fri, 12 Sep 2014 13:57:20 +1000
From:	Dave Airlie <airlied@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: vga and 64-bit memcpy's

Got an bug report from someone using a silicon motion video card in
VGA mode about corruption that they tracked down to 64-bit memory
operations not being supported by the video card, it appears that we
probably shouldn't be using > 32-bit copies on VGA memory.

The include/linux/vt_buffer.h defaults scr_memcpyw defaults to using
memcpy, which on 64-bit x86 machines ends up as rep movsq. Is there
any way to make this use a 32-bit memcpy instead?

Dave.
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