From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH 1/7] drm: Renaming DP training vswing pre emph defines Date: Wed, 27 Aug 2014 15:09:05 +0200 Message-ID: <20140827130904.GH23186@ulmo> References: <1407495226-12620-1-git-send-email-sonika.jindal@intel.com> <1407495226-12620-2-git-send-email-sonika.jindal@intel.com> <20140826112818.GA31534@ulmo> <20140827074754.GC6174@strange.amr.corp.intel.com> <20140827075135.GD6174@strange.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1045709182==" Return-path: In-Reply-To: <20140827075135.GD6174@strange.amr.corp.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Damien Lespiau Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org --===============1045709182== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ik0NlRzMGhMnxrMX" Content-Disposition: inline --ik0NlRzMGhMnxrMX Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 27, 2014 at 08:51:35AM +0100, Damien Lespiau wrote: > On Wed, Aug 27, 2014 at 08:47:54AM +0100, Damien Lespiau wrote: > > > An alternative would be to provide a second set of defines for eDP 1.4 > > > where the name implies the meaning and then use them as appropriate. > >=20 > > We went through the idea as well and: > >=20 > > I actually think the nominal voltage swing and pre-emph values are quite > > misleading. The hw is free to implement a wildly different set of volta= ge > > swing/pre-emph values. > >=20 > > eDP 1.4 changes those nominal values as described in the cover letter, > > but there again, the actual hw implementation can choose fairly > > different values than the nominal ones. > >=20 > > Also, the DP 1.2 spec documents this field as (see address 103h): > >=20 > > TRAINING_LANE0_SET : Link Training Control_Lane0 > > Bits 1:0 =3D VOLTAGE SWING SET > > 00 =E2=80=93Voltage swing level 0 > > 01 =E2=80=93Voltage swing level 1 > > 10 =E2=80=93Voltage swing level 2 > > 11 =E2=80=93Voltage swing level 3 > >=20 > > So, in that sense, we're closer to the latest spec with those LEVEL_X > > defines. >=20 > I forgot to mention here that if we have separate defines for eDP 1.4, > then we lose the possibility to share training code with big DP and eDP > 1.3, not something desirable. Yeah, I'd like to see the training sequences extracted into common helpers. Thierry --ik0NlRzMGhMnxrMX Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJT/dhwAAoJEN0jrNd/PrOhV74P/0DfoEYPnhzed0nVgAmyw5eT jTBhk8pahNUMpRx1YOtxovkGu6uIcAgzoYZF73oPt4K0n0C6BWQhchCCQm/bXdB9 1ERK0PpQj8278X1pJH2MGvJQsv/0W7jEN9GqMHEDpBQ4A/FBNv2NpaD3pqqeHXsL TbQ6IKui7hj5a361YgBlpXZinFe/zc6HPozX865rcIjAYIPfFmR641PXFMXlJMt0 xV9qLvbe5iPY3Ry1b4lYJAZEJmIbBmALS+gBD3djpMTbKoC9gdVKEHG+WcMx3vR/ UcS4Onqb4kYmAfO1X5zbhU6J0mo+1HkfQMIOJ/yqtgCpck7fLemAD32T1FG0GP1o cahz5bMGdSwoa0YiQNRMsx2Iaxyl5D5Iyz+OL3uqjLRuAUjcxtv15fjta9i7dllB FG+rWr8yst18rSbel3P89eLohxDOvgzXKmbKuQ+RBlevGKJcHk9X2+kE1q7YZIjT CldBKctyL0Yqeaqfc7YC6PvDi4jznHt/wHcPtCw3sHTxr/2yxGJCLkBj66M1aJcD 4b3AaULprih129gEYMJ1qaNpK5IHhW5LdxtUbGl3aBW+A1INsszhPKnl/GstCrhZ N089Qzrmr21t8PyRn56B3MFnmY/oxn6csN3tuyfAs3BOgNQmlcq85/FzGk+AU3V8 2qcTJ9MrmsaV893GsTE6 =lPhF -----END PGP SIGNATURE----- --ik0NlRzMGhMnxrMX-- --===============1045709182== 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 --===============1045709182==--