From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: dri-devel@lists.freedesktop.org,
Archit Taneja <architt@codeaurora.org>,
Andrzej Hajda <a.hajda@samsung.com>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Andrey Gusakov <andrey.gusakov@cogentembedded.com>,
Philipp Zabel <p.zabel@pengutronix.de>,
Chris Healy <cphealy@gmail.com>,
Lucas Stach <l.stach@pengutronix.de>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 08/15] drm/bridge: tc358767: Increase AUX transfer length limit
Date: Fri, 22 Mar 2019 12:01:07 -0700 [thread overview]
Message-ID: <CAHQ1cqExqS7kRKBX=S1_Ki_etxMyi=XRHHh7bZ1ots4Z42zyrQ@mail.gmail.com> (raw)
In-Reply-To: <7dbccf61-29fb-a6df-7f54-fd7c29bba57f@ti.com>
On Fri, Mar 22, 2019 at 6:14 AM Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
>
> On 22/03/2019 05:28, Andrey Smirnov wrote:
> > According to the datasheet tc358767 can transfer up to 16 bytes via
> > its AUX channel, so the artificial limit of 8 apperas to be too
> > low. However only up to 15-bytes seem to be actually supported and
> > trying to use 16-byte transfers results in transfers failing
> > sporadically (with bogus status in case of I2C transfers), so limit it
> > to 15.
>
> 16 is the limit from the DP spec. I agree, 8 looks odd.
>
> 15 looks odd too, so I think it warrants a comment there in the code.
>
Crap, was going to add that, but forgot. Will do in v2.
> Does 15 byte transfers ever work? Or mostly works but sometimes fails?
>
15 bytes transfers work every time (at least to extent I tested it).
For 16 byte transfers it depends on the transfer type. AUX transfers
work for a while but then fail (as tested by dd'ing AUX chardev). I2C
transfers work intermittently and when they fail return completely
bogus status.
Thanks,
Andrey Smirnov
next prev parent reply other threads:[~2019-03-22 19:01 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-22 3:28 [PATCH v2 00/15] tc358767 driver improvements Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 01/15] drm/bridge: tc358767: Simplify tc_poll_timeout() Andrey Smirnov
2019-03-22 10:12 ` Tomi Valkeinen
2019-03-22 3:28 ` [PATCH v2 02/15] drm/bridge: tc358767: Simplify polling in tc_main_link_setup() Andrey Smirnov
2019-03-22 10:13 ` Tomi Valkeinen
2019-03-22 3:28 ` [PATCH v2 03/15] drm/bridge: tc358767: Simplify polling in tc_link_training() Andrey Smirnov
2019-03-22 10:14 ` Tomi Valkeinen
2019-03-22 3:28 ` [PATCH v2 04/15] drm/bridge: tc358767: Simplify tc_set_video_mode() Andrey Smirnov
2019-03-22 10:19 ` Tomi Valkeinen
2019-03-22 17:24 ` Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 05/15] drm/bridge: tc358767: Drop custom tc_write()/tc_read() accessors Andrey Smirnov
2019-03-22 10:29 ` Tomi Valkeinen
2019-03-22 17:45 ` Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 07/15] drm/bridge: tc358767: Simplify AUX data write Andrey Smirnov
2019-03-22 10:51 ` Tomi Valkeinen
2019-03-22 17:25 ` Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 08/15] drm/bridge: tc358767: Increase AUX transfer length limit Andrey Smirnov
2019-03-22 13:14 ` Tomi Valkeinen
2019-03-22 19:01 ` Andrey Smirnov [this message]
2019-03-22 3:28 ` [PATCH v2 09/15] drm/bridge: tc358767: Use reported AUX transfer size Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 10/15] drm/bridge: tc358767: Add support for address-only I2C transfers Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 11/15] drm/bridge: tc358767: Introduce tc_set_syspllparam() Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 12/15] drm/bridge: tc358767: Introduce tc_pllupdate_pllen() Andrey Smirnov
2019-03-22 3:28 ` [PATCH v2 13/15] drm/bridge: tc358767: Simplify tc_aux_wait_busy() Andrey Smirnov
2019-03-22 3:29 ` [PATCH v2 14/15] drm/bridge: tc358767: Drop unnecessary 8 byte buffer Andrey Smirnov
2019-03-22 3:29 ` [PATCH v2 15/15] drm/bridge: tc358767: Replace magic number in tc_main_link_enable() Andrey Smirnov
2019-03-22 8:05 ` [PATCH v2 00/15] tc358767 driver improvements Tomi Valkeinen
2019-03-22 19:25 ` Andrey Smirnov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAHQ1cqExqS7kRKBX=S1_Ki_etxMyi=XRHHh7bZ1ots4Z42zyrQ@mail.gmail.com' \
--to=andrew.smirnov@gmail.com \
--cc=Laurent.pinchart@ideasonboard.com \
--cc=a.hajda@samsung.com \
--cc=andrey.gusakov@cogentembedded.com \
--cc=architt@codeaurora.org \
--cc=cphealy@gmail.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=l.stach@pengutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=p.zabel@pengutronix.de \
--cc=tomi.valkeinen@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).