From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Jackson Subject: Re: Thinkpad T420 and single/dual channel lvds Date: Wed, 14 Mar 2012 14:09:19 -0400 Message-ID: <1331748559.30864.14.camel@atropine> References: <201203141337.14798.helge.bahmann@secunet.com> <1331736306.30864.7.camel@atropine> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1129846199==" Return-path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by gabe.freedesktop.org (Postfix) with ESMTP id 7830D9E752 for ; Wed, 14 Mar 2012 11:09:24 -0700 (PDT) In-Reply-To: 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: Takashi Iwai Cc: intel-gfx@lists.freedesktop.org, hcb@chaoticmind.net List-Id: intel-gfx@lists.freedesktop.org --===============1129846199== Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-/v5q0jauEQPKQQhMdsZw" --=-/v5q0jauEQPKQQhMdsZw Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2012-03-14 at 17:44 +0100, Takashi Iwai wrote: > At Wed, 14 Mar 2012 10:45:06 -0400, > Adam Jackson wrote: > > There may or may not be a bit for this in the VBT in the BIOS. But the > > more reliably correct thing I suspect would be to just look at the > > preferred mode for the panel and assume it's dual-link LVDS if the pixe= l > > clock is >112MHz, since that's the crossover frequency. >=20 > Coincidently, we hit the same issue with a HP laptop, and wondered how > is the best way to fix. I hoped BIOS could handle better, > i.e. setting the power bits no matter whether the lid is opened or > not. But it doesn't set unless the lid is once opened. >=20 > (Interestingly, the bits remain even if you close the lid again before > booting. Just opening once seems triggering the probing of LVDS > panel in BIOS and let it setting the right values.) >=20 > FWIW, when I check ironalke_crtc_mode_set(), the clock of the HD+ > LVDS mode (1600x900) is 107800 (refclk 120000), while a similar > machine with a HD panel (1366x768) shows 76300. So, I'm not sure > whether 112MHz could be a right threshold. Hm, fair point. Would be interesting to compare the VBTs between the two boots. The lvds_fp_timing struct might actually have the data we want here regardless of how the machine booted. - ajax --=-/v5q0jauEQPKQQhMdsZw Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEABECAAYFAk9g3s8ACgkQW4otUKDs0NMSSACgpG6qmUexnk2Ha8YQ3URDS69e 7g4AoKOlLIIiYxOJBCqpzMXU93IAgytB =iXxm -----END PGP SIGNATURE----- --=-/v5q0jauEQPKQQhMdsZw-- --===============1129846199== 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 --===============1129846199==--