linux-kernel - [PATCH v2 0/2] drm/bridge: analogix_dp: Self-refresh state machine fixes

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Message-Id: <20220228202532.869740-1-briannorris@chromium.org>
Date:   Mon, 28 Feb 2022 12:25:30 -0800
From:   Brian Norris <briannorris@...omium.org>
To:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Robert Foss <robert.foss@...aro.org>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>
Cc:     dri-devel@...ts.freedesktop.org, Sean Paul <seanpaul@...omium.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Sean Paul <sean@...rly.run>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Heiko Stuebner <heiko@...ech.de>, linux-kernel@...r.kernel.org,
        Brian Norris <briannorris@...omium.org>,
        Liu Ying <victor.liu@....nxp.com>
Subject: [PATCH v2 0/2] drm/bridge: analogix_dp: Self-refresh state machine fixes

Hi,

I've been investigating several eDP issues on a Rockchip RK3399 system
and have two proposed bugfixes. RK3399 has two CRTCs, either of which
can be used for eDP output. For both fixes, we have bugs due to the
relationship between the generalized "self refresh helpers" and the
analogix-dp bridge driver which controls much of the PSR mechanics.
These bugs are most visible when switching between CRTCs.

I'm not a DRM expert, but I've been poking at a lot of Rockchip display
drivers recently. I'd love some skeptical eyes, so feel free to ask
questions if I haven't explained issues well, or the proposals look
fishy.

Regards,
Brian

Changes in v2:
- Drop "->enable" condition in crtc_needs_disable(); this could possibly
  be "->active" to reflect the intended hardware state, but it also is a
  little over-specific. We want to make a transition through "disabled"
  any time we're exiting PSR at the same time as a CRTC switch.
  (Thanks Liu Ying)

Brian Norris (2):
  drm/bridge: analogix_dp: Support PSR-exit to disable transition
  drm/atomic: Force bridge self-refresh-exit on CRTC switch

 .../drm/bridge/analogix/analogix_dp_core.c    | 42 +++++++++++++++++--
 drivers/gpu/drm/drm_atomic_helper.c           | 16 +++++--
 2 files changed, 51 insertions(+), 7 deletions(-)

-- 
2.35.1.574.g5d30c73bfb-goog