From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH] [VPG HSW-A] drm/i915: BUN vol4g[DevHSW] Vblank interrupt on disabled pipe Date: Wed, 4 Sep 2013 15:45:46 +0300 Message-ID: <20130904124546.GR11428@intel.com> References: <1378295042-12408-1-git-send-email-sandeepx.ramakutty@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mga14.intel.com (mga14.intel.com [143.182.124.37]) by gabe.freedesktop.org (Postfix) with ESMTP id 2AFFFE6F3D for ; Wed, 4 Sep 2013 05:45:51 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1378295042-12408-1-git-send-email-sandeepx.ramakutty@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Sandeep Ramankutty Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Wed, Sep 04, 2013 at 05:14:02PM +0530, Sandeep Ramankutty wrote: > This change is to comply with the BUN - Vblank interrupt on disabled pipe. > BUN states - Do not unmask and enable a vertical blank interrupt on a pipe > that is not enabled. Do not leave this interrupt enabled and unmasked aft= er > the associated pipe is disabled. If the vblank interrupt is unmasked and > enabled on a disabled pipe it will block package C3, wasting power. We mask the interrupt in IMR when we don't need it, but we do leave it enabled in IER. Is that a problem on HSW? I'm guessing not, since powertop is telling me that I'm currently reaching pc8 w/ displays off, and pc7 w/ eDP on. In any case the patch would be buggy since it has no locking around DEIER RMW accesses. But since powertop is telling me everything is already fine, we shouldn't need this patch anyway. -- = Ville Syrj=E4l=E4 Intel OTC