From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: "EDID checksum is invalid" Date: Tue, 06 Jan 2015 22:42:57 -0800 Message-ID: <86zj9vqefi.fsf@hiro.keithp.com> References: <86387nrum9.fsf@hiro.keithp.com> <20150107062109.GA32123@morell.nvidia.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0030019740==" Return-path: Received: from elaine.keithp.com (home.keithp.com [63.227.221.253]) by gabe.freedesktop.org (Postfix) with ESMTP id C8C2F6E311 for ; Tue, 6 Jan 2015 22:43:02 -0800 (PST) In-Reply-To: <20150107062109.GA32123@morell.nvidia.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Robert Morell Cc: Linus Torvalds , DRI mailing list List-Id: dri-devel@lists.freedesktop.org --===============0030019740== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Robert Morell writes: > FWIW, I've seen that exact symptom on some monitors when the +5V pin on > the DVI or HDMI cable from the GPU isn't enabled (or isn't providing > enough current). Some monitors power the i2c/edid/DDC logic from that > +5V either exclusively or when in the DPMS off state, and the i2c chip > will just stop responding after a few cycles if not provided sufficient > power. Makes sense -- the chip will power itself from the i2c when not transmitting, and can talk until whatever energy is stored in various capacitors on the Vcc rail discharge. =2D-=20 =2Dkeith --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIVAwUBVKzVcdsiGmkAAAARAQiirg//eKFLNQxCY4W451PK2y0X1KBP2KltNtUh kqboRXJKNyL1zmDvZMNb9YAR62liWa1KmHgXkSLZuybv43McVQEcDIfP7QW8pnTX 42G5HBg9EC4KCRW3cI3rjqcn+TbJWO0WLH0N9IfSQf3IaX3iOHTyx8XR52Sh3Xoa SsRoJGA4x4ZEyOZBOOz1T495PjpxCljP4g56TFDopOs0bZ4sNZOJhegpriOtXwBO rMd5BODq7WxshLJDmr7VYY/oUh2o15zTXJVWE7vQrLSP6ATzZOxqYxxfRwKb5m16 Msl042WUZCz6KGH95SYQmKXopjknIHQV54JYReiwLbQKCPmw4i5uYP6O4Zy3qAvN f5jAkQ7I7Oz+B+M+ZvG2xFp6wO/90Si7c0zLUyRCBqpfxokTcCQiUcrmVoJMGoqj ngyXdm8zdxPY4HwhRrWg1cy5zbZk6QoAfaUtmuwFeZNaYflP2dc45hz4AhmN2RWH oz/PfZyryBDLZCEuwMD8u04mTUIIYrgMGWgQLqlPCADHMxTCq9JQWVIwTQMXyynY WoWD3RtOl9wHAbhmRcuV9Q32gxw68acdwow9zAxGPiWLaXMCjNgFVBP9VzGKiD37 D5gTaijZ7MVrOu9D14tvlOpcACpoProkW0NHjRolCCuqXCAhoDj+WvZrCTIAJXSd DkB4jSYQ4zM= =PcID -----END PGP SIGNATURE----- --=-=-=-- --===============0030019740== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHA6Ly9saXN0 cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK --===============0030019740==--