From: Adam Jackson <ajax@redhat.com>
To: Keith Packard <keithp@keithp.com>
Cc: intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH] drm/i915: Hook up Ivybridge eDP
Date: Thu, 17 Nov 2011 17:45:40 -0500 [thread overview]
Message-ID: <1321569940.18123.7.camel@atropine> (raw)
In-Reply-To: <1321489780-17085-1-git-send-email-keithp@keithp.com>
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On Wed, 2011-11-16 at 16:29 -0800, Keith Packard wrote:
> The Ivybridge eDP control register looks like a cross between a
> Cougarpoint PCH DP control register and a Sandybridge eDP control
> register.
Your silicon people worry me.
> +/* IVB */
> +#define EDP_LINK_TRAIN_400MV_0DB_IVB (0x24 <<22)
> +#define EDP_LINK_TRAIN_400MV_3_5DB_IVB (0x2a <<22)
> +#define EDP_LINK_TRAIN_400MV_6DB_IVB (0x2f <<22)
> +#define EDP_LINK_TRAIN_600MV_0DB_IVB (0x30 <<22)
> +#define EDP_LINK_TRAIN_600MV_3_5DB_IVB (0x36 <<22)
> +#define EDP_LINK_TRAIN_800MV_0DB_IVB (0x38 <<22)
> +#define EDP_LINK_TRAIN_800MV_3_5DB_IVB (0x33 <<22)
> +
> +/* legacy values */
> +#define EDP_LINK_TRAIN_500MV_0DB_IVB (0x00 <<22)
> +#define EDP_LINK_TRAIN_1000MV_0DB_IVB (0x20 <<22)
> +#define EDP_LINK_TRAIN_500MV_3_5DB_IVB (0x02 <<22)
> +#define EDP_LINK_TRAIN_1000MV_3_5DB_IVB (0x22 <<22)
> +#define EDP_LINK_TRAIN_1000MV_6DB_IVB (0x23 <<22)
I don't even. Unless you're looking at some other version of the DP
spec than me, I was pretty sure those weren't legal voltage values. And
3.5dB preemph on 1000mV gives you 1500mV at the peak, which is
definitely outside the spec.
- ajax
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next prev parent reply other threads:[~2011-11-17 22:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-17 0:29 [PATCH] drm/i915: Hook up Ivybridge eDP Keith Packard
2011-11-17 22:45 ` Adam Jackson [this message]
2011-11-18 2:13 ` [Intel-gfx] " Keith Packard
2011-11-18 17:13 ` Adam Jackson
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