Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758884Ab3EFVXB (ORCPT ); Mon, 6 May 2013 17:23:01 -0400 Received: from mail-vc0-f175.google.com ([209.85.220.175]:40721 "EHLO mail-vc0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757792Ab3EFVW6 (ORCPT ); Mon, 6 May 2013 17:22:58 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Andy Lutomirski Date: Mon, 6 May 2013 14:22:37 -0700 Message-ID: Subject: Re: [PATCH 3/7] drm: Update drm_addmap and drm_mmap to use PAT WC instead of MTRRs To: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org Cc: Andy Lutomirski Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1109 Lines: 24 On Fri, May 3, 2013 at 4:00 PM, Andy Lutomirski wrote: > Signed-off-by: Andy Lutomirski > --- > > This needs careful review. I don't really know what this code does, nor > do I have the hardware. (I don't understand AGP and the associated > caching implications.) This patch is wrong (I didn't update the matching mtrr_del), and I'm reworking this whole series. But I may need some help on this one: why is the mtrr handle of a map (whatever a map is) exported to userspace via the ADD_MAP and GET_MAP ioctls? What (if anything) is userspace supposed to do with it? Do I need to return a valid MTRR register number? Is there any userspace code at all that sets _DRM_WRITE_COMBINING in DRM_IOCTL_ADD_MAP with appropriate alignment and needs the MTRR, for which the drm driver doesn't already add the MTRR? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/