linux-kernel - Re: [PATCH v3 0/3] drm/bridge: nwl-dsi: Get MIPI DSI controller and PHY ready in ->mode

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Message-ID: <YIvLQLEjWjCFVmXI@bogon.m.sigxcpu.org>
Date:   Fri, 30 Apr 2021 11:17:52 +0200
From:   Guido Günther <agx@...xcpu.org>
To:     Liu Ying <victor.liu@....com>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        a.hajda@...sung.com, narmstrong@...libre.com,
        robert.foss@...aro.org, Laurent.pinchart@...asonboard.com,
        jonas@...boo.se, jernej.skrabec@...l.net, airlied@...ux.ie,
        daniel@...ll.ch, robert.chiras@....com, linux-imx@....com
Subject: Re: [PATCH v3 0/3] drm/bridge: nwl-dsi: Get MIPI DSI controller and
 PHY ready in ->mode_set()

Hi Liu,
On Fri, Apr 23, 2021 at 05:26:40PM +0800, Liu Ying wrote:
> Hi,
> 
> This series aims to make the nwl-dsi bridge be able to connect with
> more MIPI DSI panels.  Some MIPI DSI panel drivers like 'raydium,rm68200'
> send MIPI_DCS_SET_DISPLAY_ON commands in panel_funcs->prepare(), which
> requires the MIPI DSI controller and PHY to be ready beforehand.
> However, the existing nwl-dsi driver gets the MIPI DSI controller and
> PHY ready in bridge_funcs->pre_enable(), which happens after the
> panel_funcs->prepare().  So, this series shifts the bridge operation
> ealier from bridge_funcs->pre_enable() to bridge_funcs->mode_set().
> 
> Patch 3/3 does the essential bridge operation shift.
> 
> Patch 1/3 and 2/3 are split from the original single patch in v2 and
> are needed by patch 3/3.  This split-up helps clarify changes better.
> The split-up is done in this way:
> 
> 1) Patch 1/3 forces a full modeset when crtc_state->active is changed to
>    be true(which implies only connector's DPMS is brought out of "Off"
>    status, though not necessarily).  This makes sure ->mode_set() and
>    ->atomic_disable() will be called in pairs.
> 2) Patch 2/3 removes a check on unchanged HS clock rate from ->mode_set(),
>    to make sure MIPI DSI controller and PHY are brought up and taken down
>    in pairs.
> 3) Patch 3/3 shifts the bridge operation as the last step.

Looks good to me and tested on imx8mq Librem 5 Devkit with

https://lore.kernel.org/linux-arm-kernel/cover.1617968250.git.agx@sigxcpu.org/

on top so

Reviewed-by: Guido Günther <agx@...xcpu.org>
Tested-by: Guido Günther <agx@...xcpu.org>

Cheers,
 -- Guido

> 
> 
> v2->v3:
> * Split the single patch in v2 into 3 patches. (Neil)
> 
> v1->v2:
> * Fix a typo in commit message - s/unchange/unchanged/
> 
> 
> Liu Ying (3):
>   drm/bridge: nwl-dsi: Force a full modeset when crtc_state->active is
>     changed to be true
>   drm/bridge: nwl-dsi: Remove a check on unchanged HS clock rate from
>     ->mode_set()
>   drm/bridge: nwl-dsi: Get MIPI DSI controller and PHY ready in
>     ->mode_set()
> 
>  drivers/gpu/drm/bridge/nwl-dsi.c | 86 +++++++++++++++++---------------
>  1 file changed, 46 insertions(+), 40 deletions(-)
> 
> -- 
> 2.25.1
>