From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Brian Vincent <brainn@gmail.com>,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 1/5] drm/dp/mst: Configure no_stop_bit correctly for remote i2c xfers
Date: Mon, 10 Dec 2018 18:39:28 +0200 [thread overview]
Message-ID: <20181210163928.GI9144@intel.com> (raw)
In-Reply-To: <ac9aaed5b2ea5012b750422b9c7d2fdebada61a8.camel@intel.com>
On Fri, Dec 07, 2018 at 12:45:25PM -0800, Dhinakaran Pandiyan wrote:
> On Fri, 2018-09-28 at 21:03 +0300, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > We aren't supposed to force a stop+start between every i2c msg
> > when performing multi message transfers. This should eg. cause
> > the DDC segment address to be reset back to 0 between writing
> > the segment address and reading the actual EDID extension block.
> >
> > To quote the E-DDC spec:
> > "... this standard requires that the segment pointer be
> > reset to 00h when a NO ACK or a STOP condition is received."
> Related question, do you know why the segment and ddc addresses are
> defined as 0x30 and 0x50? The E-DDC spec says they should be at 0x60
> and 0xA0/0xA1.
The spec uses 'slave_address << 1 | r/w'.
--
Ville Syrjälä
Intel
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next prev parent reply other threads:[~2018-12-10 16:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-28 18:03 [PATCH 1/5] drm/dp/mst: Configure no_stop_bit correctly for remote i2c xfers Ville Syrjala
2018-09-28 18:04 ` [PATCH 2/5] drm/dp/mst: Validate REMOTE_I2C_READ harder Ville Syrjala
2018-12-07 23:11 ` Dhinakaran Pandiyan
2018-09-28 18:04 ` [PATCH 3/5] drm/dp: Implement I2C_M_STOP for i2c-over-aux Ville Syrjala
2018-12-11 2:47 ` Dhinakaran Pandiyan
2018-12-12 10:30 ` Daniel Vetter
2018-12-12 12:12 ` Ville Syrjälä
2018-09-28 18:04 ` [PATCH 4/5] drm/dp/mst: Provide defines for ACK vs. NAK reply type Ville Syrjala
2018-12-08 0:22 ` [Intel-gfx] " Dhinakaran Pandiyan
2018-09-28 18:04 ` [PATCH 5/5] drm/dp/mst: Provide better debugs for NAK replies Ville Syrjala
2018-09-28 21:55 ` kbuild test robot
2018-12-08 0:57 ` [Intel-gfx] " Dhinakaran Pandiyan
2018-12-08 1:05 ` Dhinakaran Pandiyan
2018-12-07 20:45 ` [PATCH 1/5] drm/dp/mst: Configure no_stop_bit correctly for remote i2c xfers Dhinakaran Pandiyan
2018-12-07 22:52 ` [Intel-gfx] " Dhinakaran Pandiyan
2018-12-10 16:39 ` Ville Syrjälä [this message]
2018-12-10 20:09 ` Dhinakaran Pandiyan
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