From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: [PATCH] drm/intel: Only smash VGA SR01 register if intel is default VGA device Date: Tue, 17 Dec 2013 16:14:11 -0800 Message-ID: <868uvjrp64.fsf@miki.keithp.com> References: <1387300330-8844-1-git-send-email-keithp@keithp.com> <20131217172740.GM22448@nuc-i3427.alporthouse.com> <86bo0fs5or.fsf@miki.keithp.com> <20131217185742.GP22448@nuc-i3427.alporthouse.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0672303189==" Return-path: In-Reply-To: <20131217185742.GP22448@nuc-i3427.alporthouse.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org To: Chris Wilson Cc: Daniel Vetter , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============0672303189== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable Chris Wilson writes: > Ok, so as no vgaarb_clients have yet been registered and so the call to > grab the IO resource does not actually disable VGA IO routing to the > nvidia card. Yikes! This explains a lot. > If you care to update the changelog to explain the problem is that > vgaarb is ineffective before all clients are registered, then I think > this is a good temporary hack. It should be possible for vgaarb to mark > resources as locked if the device is interpretting IO access and has no > method for disabling the IO grab (and then a vga_tryget() check here). Sounds like vgaarb should not assume that all devices using VGA are registered drivers. That also sounds like a significantly harder fix. If SR01 is required before disabling VGA, then perhaps we should not disable VGA at all in this case though. That sounds safer, although if VGA was enabled, it will suck a bit more power? =2D-=20 keith.packard@intel.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) iQIVAwUBUrDo09siGmkAAAARAQizyBAAkpzPhAIC3btkcJzA10q1+/CX0Xjlbknq ZTkKh/09/IiYwxEp3vBZvXMnPtG4Vy+O6C/C0a360x672j49QIkeG6/IWZwcHLgO eObAKEiQOaKG55G1etYf/Sj541gV9MIH0VnjCDlzKh7s15lUgfoT2ZMTvFHKF9lt q0vzTRegphX1x5i7HtWdF/tEci5dgL8XvpV86+xDDUHoQbA1lhAkEzq+FFcMy3+8 ic67DQU9mexUse41R30pvKJDYenQRznHSBEEWxuz/8YSH1sgGC2LsMsRxI6sUQCT gX4MKdRFVkPZ6/ahrAIICQVcokdaEPW2zVPEG6dcZQic9WzzVHphBEtzvsUeSGad putqhcZlaXln0C3HVf9NU4R6YVMLuyyEDdcrtXuc9AxO8CaETGJ9GkkCAKLbKk4h jncqQ7qc2edeMVpjDk8pZtmDEf1C1+7omYSRb6GgNeCoSsM6OZlU8lTdCa+9ehBk YbhIWA30Cgp5pJhV3WoJTUm/oiVqGxujoog0QuOSCc2cYD7d+WRBatL8GxGJoWOS 3/vMtIN52pn74+xesdQff05IIkXdunQPwOoCkczC2XhMyQOqF3UsieVXIH75yQO7 rXo17mn1xY1tM7dZXC/0/zVIFXjlc5BrtHM2XgWmHdU51IaXW912qpZLXf7u8k+k FzoMovwq/bA= =ECkU -----END PGP SIGNATURE----- --=-=-=-- --===============0672303189== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx --===============0672303189==-- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752710Ab3LRAOT (ORCPT ); Tue, 17 Dec 2013 19:14:19 -0500 Received: from home.keithp.com ([63.227.221.253]:52950 "EHLO keithp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751813Ab3LRAOS (ORCPT ); Tue, 17 Dec 2013 19:14:18 -0500 From: Keith Packard To: Chris Wilson Cc: intel-gfx@lists.freedesktop.org, Daniel Vetter , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [Intel-gfx] [PATCH] drm/intel: Only smash VGA SR01 register if intel is default VGA device In-Reply-To: <20131217185742.GP22448@nuc-i3427.alporthouse.com> References: <1387300330-8844-1-git-send-email-keithp@keithp.com> <20131217172740.GM22448@nuc-i3427.alporthouse.com> <86bo0fs5or.fsf@miki.keithp.com> <20131217185742.GP22448@nuc-i3427.alporthouse.com> User-Agent: Notmuch/0.16 (http://notmuchmail.org) Emacs/23.4.1 (i486-pc-linux-gnu) Date: Tue, 17 Dec 2013 16:14:11 -0800 Message-ID: <868uvjrp64.fsf@miki.keithp.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Transfer-Encoding: quoted-printable Chris Wilson writes: > Ok, so as no vgaarb_clients have yet been registered and so the call to > grab the IO resource does not actually disable VGA IO routing to the > nvidia card. Yikes! This explains a lot. > If you care to update the changelog to explain the problem is that > vgaarb is ineffective before all clients are registered, then I think > this is a good temporary hack. It should be possible for vgaarb to mark > resources as locked if the device is interpretting IO access and has no > method for disabling the IO grab (and then a vga_tryget() check here). Sounds like vgaarb should not assume that all devices using VGA are registered drivers. That also sounds like a significantly harder fix. If SR01 is required before disabling VGA, then perhaps we should not disable VGA at all in this case though. That sounds safer, although if VGA was enabled, it will suck a bit more power? =2D-=20 keith.packard@intel.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) iQIVAwUBUrDo09siGmkAAAARAQizyBAAkpzPhAIC3btkcJzA10q1+/CX0Xjlbknq ZTkKh/09/IiYwxEp3vBZvXMnPtG4Vy+O6C/C0a360x672j49QIkeG6/IWZwcHLgO eObAKEiQOaKG55G1etYf/Sj541gV9MIH0VnjCDlzKh7s15lUgfoT2ZMTvFHKF9lt q0vzTRegphX1x5i7HtWdF/tEci5dgL8XvpV86+xDDUHoQbA1lhAkEzq+FFcMy3+8 ic67DQU9mexUse41R30pvKJDYenQRznHSBEEWxuz/8YSH1sgGC2LsMsRxI6sUQCT gX4MKdRFVkPZ6/ahrAIICQVcokdaEPW2zVPEG6dcZQic9WzzVHphBEtzvsUeSGad putqhcZlaXln0C3HVf9NU4R6YVMLuyyEDdcrtXuc9AxO8CaETGJ9GkkCAKLbKk4h jncqQ7qc2edeMVpjDk8pZtmDEf1C1+7omYSRb6GgNeCoSsM6OZlU8lTdCa+9ehBk YbhIWA30Cgp5pJhV3WoJTUm/oiVqGxujoog0QuOSCc2cYD7d+WRBatL8GxGJoWOS 3/vMtIN52pn74+xesdQff05IIkXdunQPwOoCkczC2XhMyQOqF3UsieVXIH75yQO7 rXo17mn1xY1tM7dZXC/0/zVIFXjlc5BrtHM2XgWmHdU51IaXW912qpZLXf7u8k+k FzoMovwq/bA= =ECkU -----END PGP SIGNATURE----- --=-=-=--