From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 1/4] drm/i915: save/restore the legacy backlight control Date: Tue, 28 Aug 2012 17:15:34 +0200 Message-ID: <20120828151534.GE5125@phenom.ffwll.local> References: <179a19e78c99201a9ec18967c122a5a3aedbf555.1346136448.git.jani.nikula@intel.com> <20120828141438.GC5125@phenom.ffwll.local> <4f206dd76bb01291ea6740c90ac392cc.squirrel@webmail.greenhost.nl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bk0-f49.google.com (mail-bk0-f49.google.com [209.85.214.49]) by gabe.freedesktop.org (Postfix) with ESMTP id 832D59E967 for ; Tue, 28 Aug 2012 08:15:10 -0700 (PDT) Received: by bkcji2 with SMTP id ji2so1786918bkc.36 for ; Tue, 28 Aug 2012 08:15:09 -0700 (PDT) Content-Disposition: inline In-Reply-To: <4f206dd76bb01291ea6740c90ac392cc.squirrel@webmail.greenhost.nl> 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: Indan Zupancic Cc: Jani Nikula , Takashi Iwai , intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Tue, Aug 28, 2012 at 04:49:15PM +0200, Indan Zupancic wrote: > On Tue, August 28, 2012 16:14, Daniel Vetter wrote: > > On Tue, Aug 28, 2012 at 03:56:31PM +0200, Indan Zupancic wrote: > >> Hello, > >> > >> On Tue, August 28, 2012 08:53, Jani Nikula wrote: > >> > From: Daniel Vetter > >> > > >> > This is a prep patch to stop drm/i915 from changing the LBPC registers > >> > itself - but we still need to properly save/restore it on > >> > suspend/resume. > >> > > >> > Signed-off-by: Daniel Vetter > >> > Signed-off-by: Jani Nikula > >> > --- > [...] > >> It seems weird that LBPC wouldn't be restored during resume by some BIOSes, > >> is this really necessary? > > > > ba3820ade317ee36e496b9b40d2ec3987dd4aef0 claims so. But that commit > > managed to put too many things into the same thing unfortunately. > > Is that the right SHA? Because that just reverts my combination mode > removal patch. Assuming it is the right commit, then I think it's > incorrect in saying that it caused backlight dimming problems after > resume. That particular problem was caused by a bogus shift. The > problems caused by removing the mode was a lower max brightness > and/or less brightness levels. Yeah, right commit but imo with sub-par commit message. Your other mail clarified things, thanks. > By the way, saving LBPC only makes sense if it's done before it was > set to 0 to disable the panel. I don't know if the current code does > the right thing, I haven't looked at it for a while. I think we can coax it into doing the right thing, see my other mail. If your completely sure that lbpc /should/ be handled by the bios across s/r I think we can drop this. But tbh I have no idea how this really is supposed to work, and unfortunately we're not allowed to cross-check with the windows driver codebase :( Thanks, Daniel -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48