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From: George Neacsu <geocausa@gmail.com>
To: Sergey Lebedev <lsa.uz@pm.me>
Cc: Benjamin Mugnier <benjamin.mugnier@foss.st.com>,
	Peter Marshall <pm@petermarshall.ca>,
	Sylvain Petinot <sylvain.petinot@foss.st.com>,
	Jizhou Tong <fqwqf@fqwqf.xyz>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] media: i2c: vd55g1: fix VD55G0 streaming below 900 Mbps
Date: Fri, 16 Oct 2026 11:27:09 +0100	[thread overview]
Message-ID: <20261016102709.30467-1-geocausa@gmail.com> (raw)
In-Reply-To: <20261016070158.43624-1-lsa.uz@pm.me>

Hi Sergey,

On 16/10/2026 08:02, Sergey Lebedev wrote:
> So here, writing 0 there does not stop the output by itself. vd55g1
> writes it at every stream start instead, which may be the difference.

Thanks, you are right, and it is not the place either. I retested on the
Snapdragon model with the line length change applied and 0x0329 handled
three ways:

  ISL_ENABLE = 0 at every stream start (as in Peter's v2)   6/6 captures
  ISL_ENABLE = 0 once per power-on, after boot              2/2
  never written                                              2/2

All at 840 Mbps on one lane, 644x604 Y10, with real images in every run,
including a stream-start write on the first capture after loading the
module. 0x0329 reads 0x01 after power-on here too and 0x00 once
written.

The failure I based the ISL change on came from a debug build where the
line length was forced by a register write just before stream start
rather than coming from the driver, so it was not a clean test. I will
send a v2 with only the line length change.

Thanks,
George

      reply	other threads:[~2026-10-16 10:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-16  6:37 [PATCH] media: i2c: vd55g1: fix VD55G0 streaming below 900 Mbps George Neacsu via B4 Relay
2026-10-16  6:37 ` George Neacsu
2026-10-16  7:02 ` Sergey Lebedev
2026-10-16 10:27   ` George Neacsu [this message]

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