From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Subject: Re: [PATCH] drm/i915: always set FDI composite sync bit Date: Tue, 11 Oct 2011 09:16:49 -0700 Message-ID: <20111011091649.784c9545@jbarnes-desktop> References: <1318282132-8104-1-git-send-email-jbarnes@virtuousgeek.org> <4E944E50.1070903@redhat.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1738808361==" Return-path: Received: from oproxy3-pub.bluehost.com (oproxy3-pub.bluehost.com [69.89.21.8]) by gabe.freedesktop.org (Postfix) with SMTP id 3AA1F9E734 for ; Tue, 11 Oct 2011 09:16:59 -0700 (PDT) In-Reply-To: <4E944E50.1070903@redhat.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: Adam Jackson Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org --===============1738808361== Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/RGnI4K2OnytGc899.DOrNLG"; protocol="application/pgp-signature" --Sig_/RGnI4K2OnytGc899.DOrNLG Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Tue, 11 Oct 2011 10:10:24 -0400 Adam Jackson wrote: > On 10/10/11 7:22 PM, Keith Packard wrote: > > On Mon, 10 Oct 2011 14:28:52 -0700, Jesse Barnes wrote: > > > >> It's needed for 3 pipe support as well as just regular functionality > >> (e.g. DisplayPort). > > > > Any explanation on how you get sync without this? As in, why did this > > ever work? >=20 > To a first approximation, it didn't. I was never able to get anything=20 > reliably lit up besides the boot output (and only that one; hotplug=20 > after was a disaster). >=20 > I don't have register dumps handy to compare BIOS setup with this=20 > change, but I could if needed. >=20 > It still seems entirely magical and probably wrong in some situations.=20 > And I'm thrilled to see that PPT is functionally different from CPT=20 > (seriously, stop doing that) instead of just moving bit definitions=20 > around (seriously, stop doing that). But this change is massively=20 > better than before. Without composite sync, FDI needs frame/line sync (the fsync/lsync mentioned in the docs), which means extra wires between the CPU and PCH. Some boards don't have these and so we need to use composite. For the same reason, if FDI B and C are sharing lanes, we need to use composite or we won't have enough lines to go around. I've asked the hardware guys whether using composite on a board that supports fsync/lsync is ok generally; if so just defaulting to that everywhere should be fine. --=20 Jesse Barnes, Intel Open Source Technology Center --Sig_/RGnI4K2OnytGc899.DOrNLG Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQIcBAEBAgAGBQJOlGvxAAoJEIEoDkX4Qk9h1F4P/2cnSGm5Hyi4ufX36ZkBG5t2 +LdGooKltk34mQSne4/kwFoYS/0F6FkTefoYwRMS8CAw6y/OcmtgLr0WzJp4DO+p 4EUV5apL02+/6LR5cMYOAjk+IoAcN/d4mEAPuodHCzbwXvz/va+ZxP5JCBRM35bj rJXan66UVorBgdEYPJgQkohynXOSE2YvmYIzdz/YKtxux3R9Ie3f7h9fa5waDSTk lhpieJUQIwG6ZM7RbQlcHaPVLS+WR/qEJPNmIIGcdw40GqdFeTMVWnRpFQ7wMShQ jViNBgxKtITawW0jZNfFoTWO9VYAeXtr1WPiE838nIHyuqG5yIGTJ4/tgTIZzbox jE96VeTpvRaB7f8/DFJv/Gmo5/tacjLjgE7IqgaZJ5OXKvxfA3zLuWsYOvoExnq/ 3C6nO02mkxBsxE2pHmIj4cmNroZJpEFzfqpcPDS4d2bB/4mqw13Pueq6/h4uxPrt Pb3Caru8cCUu5DA5Vtwt1Tzs2AUaUHvSiBJdRqsVyw1qbFDK53ZZMh/ZvwKFOoAX L/UyChj1LLfRHTBCoDX/fQW+O/+Ek2YXDk/DmqbMsSrxXP4snlvba2aj4jgYWSAI BNL9wnUGd/4tjh8pumqbN2vWlGCn2Shyrb6wg0LPc7zND0w7RIooMy46waBEsQmE lryw3iv+NsVMY68GgaWY =Ow6V -----END PGP SIGNATURE----- --Sig_/RGnI4K2OnytGc899.DOrNLG-- --===============1738808361== 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 --===============1738808361==--