From patchwork Thu Aug 15 22:37:59 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 2845299 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 536CC9F2F5 for ; Thu, 15 Aug 2013 22:39:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6948020357 for ; Thu, 15 Aug 2013 22:38:59 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 89DD720348 for ; Thu, 15 Aug 2013 22:38:58 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7888DE84FA for ; Thu, 15 Aug 2013 15:38:58 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by gabe.freedesktop.org (Postfix) with ESMTP id E95C4E8507 for ; Thu, 15 Aug 2013 15:38:00 -0700 (PDT) Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r7FMc0Oi027147 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 15 Aug 2013 18:38:00 -0400 Received: from bling.home (ovpn-113-74.phx2.redhat.com [10.3.113.74]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r7FMbxIZ032584; Thu, 15 Aug 2013 18:37:59 -0400 To: linux-kernel@vger.kernel.org From: Alex Williamson Date: Thu, 15 Aug 2013 16:37:59 -0600 Message-ID: <20130815223759.27642.50609.stgit@bling.home> In-Reply-To: <20130815222835.27642.15330.stgit@bling.home> References: <20130815222835.27642.15330.stgit@bling.home> User-Agent: StGit/0.16 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 Cc: airlied@redhat.com, intel-gfx@lists.freedesktop.org Subject: [Intel-gfx] [PATCH 2/2] vgaarb: Fix VGA decodes changes X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org X-Spam-Status: No, score=-7.0 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When VGA decodes change we need to do a bit more evaluation of exactly what has changed. We don't necessarily give up all the old owns resources and we need to account for resources with locks. The new algorithm is: If something is added, update decodes. If legacy resources were added and none were there before, we have a new participant. If something is removed, update decodes. If we previously owned it, we no longer own it. If it was previously locked, invalidate all locks and release it. If legacy resources were removed and none are left, remove the participant from VGA arbitration. Previously we updated decodes, released ownership of everything that was previously decoded, ignored all locks, and went off looking for another device to transfer VGA to. In a test case where Intel IGD removes only legacy VGA memory decoding, this left the arbiter switching to discrete graphics without actually disabling legacy VGA IO from the IGD. As a bonus, we bumped up the count of VGA arbitration participants for no good reason. Signed-off-by: Alex Williamson Cc: Dave Airlie --- drivers/gpu/vga/vgaarb.c | 40 +++++++++++++++++----------------------- 1 file changed, 17 insertions(+), 23 deletions(-) diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c index ea56471..4ee444c 100644 --- a/drivers/gpu/vga/vgaarb.c +++ b/drivers/gpu/vga/vgaarb.c @@ -644,10 +644,13 @@ bail: static inline void vga_update_device_decodes(struct vga_device *vgadev, int new_decodes) { - int old_decodes; + int old_decodes, decodes_removed, decodes_unlocked; struct vga_device *new_vgadev, *conflict; old_decodes = vgadev->decodes; + decodes_removed = ~new_decodes & old_decodes; + decodes_unlocked = vgadev->locks & decodes_removed; + vgadev->owns &= ~decodes_removed; vgadev->decodes = new_decodes; pr_info("vgaarb: device changed decodes: PCI:%s,olddecodes=%s,decodes=%s:owns=%s\n", @@ -656,31 +659,22 @@ static inline void vga_update_device_decodes(struct vga_device *vgadev, vga_iostate_to_str(vgadev->decodes), vga_iostate_to_str(vgadev->owns)); - - /* if we own the decodes we should move them along to - another card */ - if ((vgadev->owns & old_decodes) && (vga_count > 1)) { - /* set us to own nothing */ - vgadev->owns &= ~old_decodes; - list_for_each_entry(new_vgadev, &vga_list, list) { - if ((new_vgadev != vgadev) && - (new_vgadev->decodes & VGA_RSRC_LEGACY_MASK)) { - pr_info("vgaarb: transferring owner from PCI:%s to PCI:%s\n", pci_name(vgadev->pdev), pci_name(new_vgadev->pdev)); - conflict = __vga_tryget(new_vgadev, VGA_RSRC_LEGACY_MASK); - if (!conflict) - __vga_put(new_vgadev, VGA_RSRC_LEGACY_MASK); - break; - } - } + /* if we removed locked decodes, lock count goes to zero, and release */ + if (decodes_unlocked) { + if (decodes_unlocked & VGA_RSRC_LEGACY_IO) + vgadev->io_lock_cnt = 0; + if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) + vgadev->mem_lock_cnt = 0; + __vga_put(vgadev, decodes_unlocked); } /* change decodes counter */ - if (old_decodes != new_decodes) { - if (new_decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) - vga_decode_count++; - else - vga_decode_count--; - } + if (old_decodes & VGA_RSRC_LEGACY_MASK && + !(new_decodes & VGA_RSRC_LEGACY_MASK)) + vga_decode_count--; + if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && + new_decodes & VGA_RSRC_LEGACY_MASK) + vga_decode_count++; pr_debug("vgaarb: decoding count now is: %d\n", vga_decode_count); }