From: Keith Packard <keithp@keithp.com>
To: Robert Morell <rmorell@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
DRI mailing list <dri-devel@lists.freedesktop.org>
Subject: Re: "EDID checksum is invalid"
Date: Tue, 06 Jan 2015 22:42:57 -0800 [thread overview]
Message-ID: <86zj9vqefi.fsf@hiro.keithp.com> (raw)
In-Reply-To: <20150107062109.GA32123@morell.nvidia.com>
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Robert Morell <rmorell@nvidia.com> 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.
--
-keith
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next prev parent reply other threads:[~2015-01-07 6:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-07 2:01 "EDID checksum is invalid" Linus Torvalds
2015-01-07 6:07 ` Keith Packard
2015-01-07 6:21 ` Robert Morell
2015-01-07 6:42 ` Keith Packard [this message]
2015-01-07 17:07 ` Linus Torvalds
2015-01-07 17:51 ` Daniel Vetter
2015-01-07 18:03 ` Linus Torvalds
2015-01-08 7:05 ` Keith Packard
2015-01-07 7:32 ` Daniel Vetter
2015-01-07 17:51 ` Linus Torvalds
2015-01-07 20:06 ` Daniel Vetter
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