Message-ID: <9c2c151d-f210-4fbc-af7c-d6aa5838cede@ideasonboard.com>
Date: Tue, 3 Jun 2025 15:48:26 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Thomas Zimmermann <tzimmermann@...e.de>, Maxime Ripard <mripard@...nel.org>
Cc: Nishanth Menon <nm@...com>, Vignesh Raghavendra <vigneshr@...com>,
 Devarsh Thakkar <devarsht@...com>, Praneeth Bajjuri <praneeth@...com>,
 Udit Kumar <u-kumar1@...com>, Jayesh Choudhary <j-choudhary@...com>,
 Alexander Sverdlin <alexander.sverdlin@...mens.com>,
 DRI Development List <dri-devel@...ts.freedesktop.org>,
 Linux Kernel List <linux-kernel@...r.kernel.org>,
 Aradhya Bhatia <aradhya.bhatia@...ux.dev>,
 Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
 Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 Andrzej Hajda <andrzej.hajda@...el.com>,
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Subject: Re: [PATCH v12 0/5] drm/atomic-helper: Re-order CRTC and Bridge ops

Hi Maxime, Maarten, Thomas,

(You're the first three names returned with get_maintainers.pl =), so:)

Ping on this.

 Tomi

On 26/05/2025 13:40, Tomi Valkeinen wrote:
> Hi Maxime, Maarten, Thomas,
> 
> On 16/05/2025 15:23, Tomi Valkeinen wrote:
>> Hi all,
>>
>> On 06/04/2025 16:16, Aradhya Bhatia wrote:
>>> Hello all,
>>>
>>> This series re-orders the sequences in which the drm CRTC and the drm
>>> Bridge get enabled and disabled with respect to each other.
>>>
>>> The bridge pre_enable calls have been shifted before the crtc_enable and
>>> the bridge post_disable calls have been shifted after the crtc_disable.
>>>
>>> This has been done as per the definition of bridge pre_enable.
>>> "The display pipe (i.e. clocks and timing signals) feeding this bridge
>>> will
>>> not yet be running when this callback is called".
>>>
>>> Since CRTC is also a source feeding the bridge, it should not be enabled
>>> before the bridges in the pipeline are pre_enabled.
>>
>> Any further comments to this?
>>
>> All the patches have been reviewed and tested. I can push this, along
>> with the serieses that depend on this, via drm-misc, but I'll need an
>> ack from a maintainer.
> 
> Would any of you have a moment to check this out and ack/apply? This
> series is blocking further development on DSI and OLDI.
> 
>  Tomi
> 
>>
>>  Tomi
>>
>>
>>> The original sequence. for display pipe enable looks like:
>>>
>>>        crtc_enable
>>>
>>>        bridge[n]_pre_enable
>>>        ...
>>>        bridge[1]_pre_enable
>>>
>>>        encoder_enable
>>>
>>>        bridge[1]_enable
>>>        ...
>>>        bridge[n]_enable
>>>
>>> The sequence of enable after this patch-set will look like:
>>>
>>>        bridge[n]_pre_enable
>>>        ...
>>>        bridge[1]_pre_enable
>>>
>>>        crtc_enable
>>>        encoder_enable
>>>
>>>        bridge[1]_enable
>>>        ...
>>>        bridge[n]_enable
>>>
>>>
>>> For the disable sequence, this is what the original looks like:
>>>
>>>        bridge[n]_disable
>>>        ...
>>>        bridge[1]_disable
>>>
>>>        encoder_disable
>>>
>>>        bridge[1]_post_disable
>>>        ...
>>>        bridge[n]_post_disable
>>>
>>>        crtc_disable
>>>     
>>> This is what the disable sequence will be, after this series of patches:
>>>
>>>        bridge[n]_disable
>>>        ...
>>>        bridge[1]_disable
>>>
>>>        encoder_disable
>>>        crtc_disable
>>>
>>>        bridge[1]_post_disable
>>>        ...
>>>        bridge[n]_post_disable
>>>
>>> This series further updates the bridge API definitions to accurately
>>> reflect the updated scenario.
>>>
>>> This series is a subset of its v11[0] which had 14 patches in the
>>> revision.
>>> 9 of those 14 patches (which were specific to the cdns-dsi bridge driver)
>>> were merged[1].
>>>
>>> Regards
>>> Aradhya
>>>
>>> ---
>>> * Note on checkpatch warning in patch 2/4 *
>>> Patch 2/4 causes the checkpatch to flare up for 1 checkpatch 'check' -
>>>
>>> CHECK: Lines should not end with a '('
>>> #79: FILE: drivers/gpu/drm/drm_atomic_helper.c:1304:
>>> +                       new_crtc_state = drm_atomic_get_new_crtc_state(
>>>
>>> This patch is largely duplicating the original code, with minor
>>> differences to
>>> perform different operations. This line of code pre-exists in the file
>>> and
>>> have simply been duplicated. I have decided to keep it as is to
>>> maintain the
>>> uniformity and the originally intended readability. Should perhaps a
>>> fix be
>>> required, this patch/series is not the right place, and another patch
>>> can be
>>> created to fix this across the whole file.
>>>
>>> References:
>>> [0]: Revision v11 of this series.
>>> https://lore.kernel.org/all/20250329113925.68204-1-
>>> aradhya.bhatia@...ux.dev/
>>>
>>> [1]: Patches 1 through 9 getting merged.
>>> https://lore.kernel.org/
>>> all/174335361171.2556605.12634785416741695829.b4-ty@....qualcomm.com/
>>>
>>>
>>> ---
>>> Change Log:
>>>
>>>    - Changes in v12:
>>>      - Drop patches 1 through 9 since they have been merged.
>>>      - Rebase onto newer drm-misc-next.
>>>      - Re-word the patch 3/4, ("drm/bridge: Update the bridge enable/
>>> disable doc")
>>>        to make it more readable.
>>>
>>>    - Changes in v11:
>>>      - Add patch v11:13/14 ("drm/bridge: Update the bridge enable/
>>> disable doc"),
>>>        that updates the documentation about the order of the various
>>> bridge
>>>        enable/disable hooks being called wrt the CRTC and encoder hooks.
>>>      - Rebase on drm-misc-next instead of linux-next.
>>>        As part of rebase, accommodate the following change:
>>>        - Change patch v10:08/13 ("drm/bridge: cdns-dsi: Support atomic
>>> bridge
>>>          APIs") to v11:08/13 ("drm/bridge: cdns-dsi: Add input format
>>>          negotiation"), since Maxime has already updated the bridge
>>> hooks to
>>>          their atomic versions in commit 68c98e227a96 ("drm/bridge:
>>> cdns-csi:
>>>          Switch to atomic helpers").
>>>          My new patch now only adds the format negotiation hook for
>>> the cdns-dsi.
>>>          (Note: Since the new patch is now only a subset of the old
>>> one, without
>>>          any change in logic, I decided to carry forward the R-b and
>>> T-b tags.)
>>>      - Add Alexander Sverdlin's T-b in patches 10, 11, 12.
>>>
>>>    - Changes in v10:
>>>      - Rebase on latest linux-next (next-20250226).
>>>      - As part of rebase, update the patches to accommodate a couple of
>>>        widespread changes in DRM Framework -
>>>          - All the ("drm/atomic-helper: Change parameter name of ***")
>>> commits.
>>>          - All the ("drm/bridge: Pass full state to ***") commits.
>>>        (These updates are only trivial substitutions.)
>>>      - Add Tomi Valkeinen's T-b tags in all the patches.
>>>
>>>    - Changes in v9:
>>>      - Fix the oops in 11/13 - where the encoder_bridge_enable _was_
>>> pre_enabling
>>>        the bridges instead of enabling.
>>>      - Add the following tags:
>>>        - Dmitry Baryshkov's R-b in patches 2, 10, 11, and A-b in patch
>>> 12.
>>>        - Jayesh Choudhary's R-b in patch 12.
>>>        - Tomi Valkeinen's R-b in patches 2, 10, 11, 12.
>>>
>>>    - Changes in v8:
>>>      - Move the phy de-initialization to bridge post_disable() instead
>>> of bridge
>>>        disable() in patch-3.
>>>      - Copy the private bridge state (dsi_cfg), in addition to the
>>> bridge_state,
>>>        in patch-9.
>>>      - Split patch v7:11/12 into three patches, v8:{10,11,12}/13, to
>>> separate out
>>>        different refactorings into different patches, and improve
>>> bisectability.
>>>      - Move patch v7:02/12 down to v8:06/12, to keep the initial
>>> patches for
>>>        fixes only.
>>>      - Drop patch v7:04/12 as it doesn't become relevant until patch
>>> v7:12/12.
>>>      - Add R-b tags of Dmitry Baryshkov in patch-9 and patch-3, and of
>>>        Tomi Valkeinen in patch-9.
>>>        - Changes in v7:
>>>      - phy_init()/exit() were called from the PM path in v6. Change it
>>> back to
>>>        the bridge enable/disable path in patch-3, so that the
>>> phy_init() can go
>>>        back to being called after D-Phy reset assert.
>>>      - Reword commit text in patch-5 to explain the need of the fix.
>>>      - Drop the stray code in patch-10.
>>>      - Add R-b tag of Dmitry Baryshkov in patch-6.
>>>
>>>    - Changes in v6:
>>>      - Reword patch 3 to better explain the fixes around phy de-init.
>>>      - Fix the Lane ready timeout condition in patch 7.
>>>      - Fix the dsi _bridge_atomic_check() implementation by adding a new
>>>        bridge state structure in patch 10.
>>>      - Rework and combine patches v5:11/13 and v5:12/13 to v6:11/12.
>>>      - Generate the patches of these series using the "patience"
>>> algorithm.
>>>        Note: All patches, except v6:11/12, *do not* differ from their
>>> default
>>>        (greedy) algorithm variants.
>>>        For patch 11, the patience algorithm significantly improves the
>>> readability.
>>>      - Rename and move the Bridge enable/disable enums from public to
>>> private
>>>        in patch 11.
>>>      - Add R-b tags of Tomi Valkeinen in patch 6, and Dmitry Baryshkov
>>> in patch 2.
>>>
>>>    - Changes in v5:
>>>      - Fix subject and description in patch 1/13.
>>>      - Add patch to check the return value of
>>>        phy_mipi_dphy_get_default_config() (patch: 6/13).
>>>      - Change the Clk and Data Lane ready timeout from forever to 5s.
>>>      - Print an error instead of calling WARN_ON_ONCE in patch 7/13.
>>>      - Drop patch v4-07/11: "drm/bridge: cdns-dsi: Reset the DCS write
>>> FIFO".
>>>        There has been some inconsistencies found with this patch upon
>>> further
>>>        testing. This patch was being used to enable a DSI panel based
>>> on ILITEK
>>>        ILI9881C bridge. This will be debugged separately.
>>>      - Add patch to move the DSI mode check from _atomic_enable() to
>>>        _atomic_check() (patch: 10/13).
>>>      - Split patch v4-10/11 into 2 patches - 11/13 and 12/13.
>>>        Patch 11/13 separates out the Encoder-Bridge operations into a
>>> helper
>>>        function *without* changing the logic. Patch 12/13 then changes
>>> the order
>>>        of the encoder-bridge operations as was intended in the
>>> original patch.
>>>      - Add detailed comment for patch 13/13.
>>>      - Add Tomi Valkeinen's R-b in patches 1, 2, 4, 5, 7, 8, 9, 13.
>>>
>>>    - Changes in v4:
>>>      - Add new patch, "drm/bridge: cdns-dsi: Move to
>>> devm_drm_of_get_bridge()",
>>>        to update to an auto-managed way of finding next bridge in the
>>> chain.
>>>      - Drop patch "drm/bridge: cdns-dsi: Fix the phy_initialized
>>> variable" and
>>>        add "drm/bridge: cdns-dsi: Fix Phy _init() and _exit()" that
>>> properly
>>>        de-initializes the Phy and maintains the initialization state.
>>>      - Reword patch "drm/bridge: cdns-dsi: Reset the DCS write FIFO"
>>> to explain
>>>        the HW concerns better.
>>>      - Add R-b tag from Dmitry Baryshkov for patches 1/11 and 8/11.
>>>
>>>    - Changes in v3:
>>>      - Reword the commit message for patch "drm/bridge: cdns-dsi: Fix
>>> OF node
>>>        pointer".
>>>      - Add a new helper API to figure out DSI host input pixel format
>>>        in patch "drm/mipi-dsi: Add helper to find input format".
>>>      - Use a common function for bridge pre-enable and enable, and
>>> bridge disable
>>>        and post-disable, to avoid code duplication.
>>>      - Add T-b tag from Dominik Haller in patch 5/10. (Missed to add
>>> it in v2).
>>>      - Add R-b tag from Dmitry Baryshkov for patch 8/10.
>>>
>>>    - Changes in v2:
>>>      - Drop patch "drm/tidss: Add CRTC mode_fixup"
>>>      - Split patch "drm/bridge: cdns-dsi: Fix minor bugs" into 4
>>> separate ones
>>>      - Drop support for early_enable/late_disable APIs and instead re-
>>> order the
>>>        pre_enable / post_disable APIs to be called before / after
>>> crtc_enable /
>>>        crtc_disable.
>>>      - Drop support for early_enable/late_disable in cdns-dsi and use
>>>        pre_enable/post_disable APIs instead to do bridge enable/disable.
>>>
>>>
>>> Previous versions:
>>>
>>> v1:  https://lore.kernel.org/all/20240511153051.1355825-1-a-
>>> bhatia1@...com/
>>> v2:  https://lore.kernel.org/all/20240530093621.1925863-1-a-
>>> bhatia1@...com/
>>> v3:  https://lore.kernel.org/all/20240617105311.1587489-1-a-
>>> bhatia1@...com/
>>> v4:  https://lore.kernel.org/all/20240622110929.3115714-1-a-
>>> bhatia1@...com/
>>> v5:  https://lore.kernel.org/all/20241019195411.266860-1-
>>> aradhya.bhatia@...ux.dev/
>>> v6:  https://lore.kernel.org/all/20250111192738.308889-1-
>>> aradhya.bhatia@...ux.dev/
>>> v7:  https://lore.kernel.org/all/20250114055626.18816-1-
>>> aradhya.bhatia@...ux.dev/
>>> v8:  https://lore.kernel.org/all/20250126191551.741957-1-
>>> aradhya.bhatia@...ux.dev/
>>> v9:  https://lore.kernel.org/all/20250209121032.32655-1-
>>> aradhya.bhatia@...ux.dev/
>>> v10: https://lore.kernel.org/all/20250226155228.564289-1-
>>> aradhya.bhatia@...ux.dev/
>>> v11: https://lore.kernel.org/all/20250329113925.68204-1-
>>> aradhya.bhatia@...ux.dev/
>>>
>>> ---
>>>
>>> Aradhya Bhatia (5):
>>>    drm/atomic-helper: Refactor crtc & encoder-bridge op loops into
>>>      separate functions
>>>    drm/atomic-helper: Separate out bridge pre_enable/post_disable from
>>>      enable/disable
>>>    drm/atomic-helper: Re-order bridge chain pre-enable and post-disable
>>>    drm/bridge: Update the bridge enable/disable doc
>>>    drm/bridge: cdns-dsi: Use pre_enable/post_disable to enable/disable
>>>
>>>   .../gpu/drm/bridge/cadence/cdns-dsi-core.c    |  64 +++--
>>>   drivers/gpu/drm/drm_atomic_helper.c           | 160 +++++++++--
>>>   include/drm/drm_bridge.h                      | 249 +++++++++++++-----
>>>   3 files changed, 355 insertions(+), 118 deletions(-)
>>>
>>>
>>> base-commit: dd717762761807452ca25634652e180a80349cd8
>>
> 

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