From patchwork Mon May 13 23:58:43 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 2561281 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id AC3A0DF2E5 for ; Tue, 14 May 2013 00:00:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755501Ab3EMX7N (ORCPT ); Mon, 13 May 2013 19:59:13 -0400 Received: from mail-pb0-f47.google.com ([209.85.160.47]:44506 "EHLO mail-pb0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755680Ab3EMX7J (ORCPT ); Mon, 13 May 2013 19:59:09 -0400 Received: by mail-pb0-f47.google.com with SMTP id rr4so1596194pbb.34 for ; Mon, 13 May 2013 16:59:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-received:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references:in-reply-to:references:x-gm-message-state; bh=tUx8Ww8i9kW0pW+6NciBx0tusB8MHPKZ7j9+Obd0HHo=; b=RPr0WeXnTb+71Tc+gtG2NTmtHE7j/wKewxAXl/tOXHge0Sx6oq7zw4wRBDKCBhfs3Y H3WEByM0LspxGnr8UKo47lNdURhQqJ7wya3kys3md8Kb+aJwLfXl7GQxsMrMJEmHq4cr /LnPXA22if5TGvPa6elIbJH0yM2KAs0AO6bVjzHt/F65vbeeZXFEQhpbgulH4i7biaDB 8cOMR8UBKc4f8SHHy9xsoEKKzk2VPV0LOqXo1WKzOz9ZgTKz7XdW/S1TMvHfq5ruNY27 7UXOZ2M3VX3N5fHSMWaBOOS/zDRV7JDlsLJji+hsGi2ZmN2H1UJ4Ep71pZ7U+mzMJyeW a7Wg== X-Received: by 10.68.218.34 with SMTP id pd2mr31162554pbc.204.1368489548616; Mon, 13 May 2013 16:59:08 -0700 (PDT) Received: from localhost (50-76-60-73-ip-static.hfc.comcastbusiness.net. [50.76.60.73]) by mx.google.com with ESMTPSA id v5sm15715103pbz.4.2013.05.13.16.59.06 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Mon, 13 May 2013 16:59:07 -0700 (PDT) From: Andy Lutomirski To: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org Cc: Daniel Vetter , Jerome Glisse , Alex Deucher , Dave Airlie , Andy Lutomirski Subject: [PATCH v3 4/9] drm, agpgart: Use pgprot_writecombine for AGP maps and make the MTRR optional Date: Mon, 13 May 2013 16:58:43 -0700 Message-Id: <809e6805f78212758097c0a74f9f59053cfdafaf.1368485053.git.luto@amacapital.net> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: References: In-Reply-To: References: X-Gm-Message-State: ALoCoQl8QlX1v2QOs+qD9ZDut6793a/j0lUatblKnsf14wHM4BsKaVz5eFxW/uaXl+AFh+hRBhLG Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org I'm not sure I understand the intent of the previous behavior. mmap on /dev/agpgart and DRM_AGP maps had no cache flags set, so they would be fully cacheable. But the DRM code (most of the time) would add a write-combining MTRR that would change the effective memory type to WC. The new behavior just requests WC explicitly for all AGP maps. If there is any code out there that expects cacheable access to the AGP aperture (because the drm driver doesn't request an MTRR or because it's using /dev/agpgart directly), then it will now end up with a UC or WC mapping, depending on the architecture and PAT availability. But cacheable access to the aperture seems like it's asking for trouble, because, AIUI, the aperture is an alias of RAM. Reviewed-by: Daniel Vetter Signed-off-by: Andy Lutomirski --- It's conceivable that libpciaccess could have issues with this due to memtype conflicts, but I think this is unlikely (as long as a WC mapping gets there first, I think the conflict resolution rules will all work out). In any case, everything that maps the AGP aperture ought to be using /dev/agpgart or the DRM API, in which case everything should be okay. I don't have anything with an AGP slot to test AFAIK. drivers/char/agp/frontend.c | 8 +++++--- drivers/gpu/drm/drm_pci.c | 8 ++++---- drivers/gpu/drm/drm_stub.c | 10 ++-------- drivers/gpu/drm/drm_vm.c | 11 ++++------- 4 files changed, 15 insertions(+), 22 deletions(-) diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c index 2e04433..1b19239 100644 --- a/drivers/char/agp/frontend.c +++ b/drivers/char/agp/frontend.c @@ -603,7 +603,8 @@ static int agp_mmap(struct file *file, struct vm_area_struct *vma) vma->vm_ops = kerninfo.vm_ops; } else if (io_remap_pfn_range(vma, vma->vm_start, (kerninfo.aper_base + offset) >> PAGE_SHIFT, - size, vma->vm_page_prot)) { + size, + pgprot_writecombine(vma->vm_page_prot))) { goto out_again; } mutex_unlock(&(agp_fe.agp_mutex)); @@ -618,8 +619,9 @@ static int agp_mmap(struct file *file, struct vm_area_struct *vma) if (kerninfo.vm_ops) { vma->vm_ops = kerninfo.vm_ops; } else if (io_remap_pfn_range(vma, vma->vm_start, - kerninfo.aper_base >> PAGE_SHIFT, - size, vma->vm_page_prot)) { + kerninfo.aper_base >> PAGE_SHIFT, + size, + pgprot_writecombine(vma->vm_page_prot))) { goto out_again; } mutex_unlock(&(agp_fe.agp_mutex)); diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c index bd719e9..d0f6699 100644 --- a/drivers/gpu/drm/drm_pci.c +++ b/drivers/gpu/drm/drm_pci.c @@ -278,10 +278,10 @@ int drm_pci_agp_init(struct drm_device *dev) } if (drm_core_has_MTRR(dev)) { if (dev->agp) - dev->agp->agp_mtrr = - mtrr_add(dev->agp->agp_info.aper_base, - dev->agp->agp_info.aper_size * - 1024 * 1024, MTRR_TYPE_WRCOMB, 1); + dev->agp->agp_mtrr = arch_phys_wc_add( + dev->agp->agp_info.aper_base, + dev->agp->agp_info.aper_size * + 1024 * 1024); } } return 0; diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c index 7d30802..9e2acdf 100644 --- a/drivers/gpu/drm/drm_stub.c +++ b/drivers/gpu/drm/drm_stub.c @@ -451,14 +451,8 @@ void drm_put_dev(struct drm_device *dev) drm_lastclose(dev); - if (drm_core_has_MTRR(dev) && drm_core_has_AGP(dev) && - dev->agp && dev->agp->agp_mtrr >= 0) { - int retval; - retval = mtrr_del(dev->agp->agp_mtrr, - dev->agp->agp_info.aper_base, - dev->agp->agp_info.aper_size * 1024 * 1024); - DRM_DEBUG("mtrr_del=%d\n", retval); - } + if (drm_core_has_MTRR(dev) && drm_core_has_AGP(dev) && dev->agp) + arch_phys_wc_del(dev->agp->agp_mtrr); if (dev->driver->unload) dev->driver->unload(dev); diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c index 163f436..b1e4ec8 100644 --- a/drivers/gpu/drm/drm_vm.c +++ b/drivers/gpu/drm/drm_vm.c @@ -49,13 +49,10 @@ static pgprot_t drm_io_prot(struct drm_local_map *map, pgprot_t tmp = vm_get_page_prot(vma->vm_flags); #if defined(__i386__) || defined(__x86_64__) - if (map->type != _DRM_AGP) { - if (map->type == _DRM_FRAME_BUFFER || - map->flags & _DRM_WRITE_COMBINING) - tmp = pgprot_writecombine(tmp); - else - tmp = pgprot_noncached(tmp); - } + if (map->type == _DRM_REGISTERS && !(map->flags & _DRM_WRITE_COMBINING)) + tmp = pgprot_noncached(tmp); + else + tmp = pgprot_writecombine(tmp); #elif defined(__powerpc__) pgprot_val(tmp) |= _PAGE_NO_CACHE; if (map_type == _DRM_REGISTERS)