On 5/13/24 9:57 AM, Marek Szyprowski wrote:

On 13.05.2024 04:16, Marek Vasut wrote:
Initialize the bridge on attach already, to force lanes into LP11
state, since attach does trigger attach of downstream bridges which
may trigger (e)DP AUX channel mode read.

This fixes a corner case where DSIM with TC9595 attached to it fails
to operate the DP AUX channel, because the TC9595 enters some debug
mode when it is released from reset without lanes in LP11 mode. By
ensuring the DSIM lanes are in LP11, the TC9595 (tc358767.c driver)
can be reset in its attach callback called from DSIM attach callback,
and recovered out of the debug mode just before TC9595 performs first
AUX channel access later in its attach callback.

Signed-off-by: Marek Vasut <ma...@denx.de>

This patch breaks driver operation on Samsung TM2e board with S6E3HF2
DSI panel. The initialization procedure is very fragile and it looks
that the changes must be done very carefully. We discussed this many
times when converting this driver from Exynos DSI to generic Samsung DSI
used on IMX and other SoCs.

Clearly we need to find a way to support both use cases .

What options do we have ?

Does the panel require DSI lanes in some specific state when it is released from reset ?

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