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Message-ID: <nm7nwmftzsjafovdprobzpuat6hrm6rghishgywww7qtul5skp@mihpqbpre3e5>
Date: Sat, 17 Jun 2023 19:39:22 +0200
From: Ondřej Jirman <megi@....cz>
To: Sam Ravnborg <sam@...nborg.org>
Cc: linux-rockchip@...ts.infradead.org,
Neil Armstrong <neil.armstrong@...aro.org>,
Robert Foss <rfoss@...nel.org>,
Jonas Karlman <jonas@...boo.se>,
"open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
open list <linux-kernel@...r.kernel.org>,
Jernej Skrabec <jernej.skrabec@...il.com>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Andrzej Hajda <andrzej.hajda@...el.com>
Subject: Re: [PATCH] drm: bridge: dw-mipi-dsi: Fix enable/disable of DSI
controller
Hello Sam,
On Sat, Jun 17, 2023 at 07:35:53PM +0200, Sam Ravnborg wrote:
>
> Hi Ondřej,
>
> On Sat, Jun 17, 2023 at 05:06:33PM +0200, Ondřej Jirman wrote:
> > From: Ondrej Jirman <megi@....cz>
> >
> > Before this patch, booting to Linux VT and doing a simple:
> >
> > echo 2 > /sys/class/graphics/fb0/blank
> > echo 0 > /sys/class/graphics/fb0/blank
> >
> > would result in failures to re-enable the panel. Mode set callback is
> > called only once during boot in this scenario, while calls to
> > enable/disable callbacks are balanced afterwards. The driver doesn't
> > work unless userspace calls modeset before enabling the CRTC/connector.
> >
> > This patch moves enabling of the DSI host from mode_set into pre_enable
> > callback, and removes some old hacks where this bridge driver is
> > directly calling into other bridge driver's callbacks.
> >
> > pre_enable_prev_first flag is set on the panel's bridge so that panel
> > drivers will get their prepare function called between DSI host's
> > pre_enable and enable callbacks, so that they get a chance to
> > perform panel setup while DSI host is already enabled in command
> > mode. Otherwise panel's prepare would be called before DSI host
> > is enabled, and any DSI communication used in prepare callback
> > would fail.
> >
> > With all these changes, the enable/disable sequence is now well
> > balanced, and host's and panel's callbacks are called in proper order
> > documented in the drm_panel API documentation without needing the old
> > hacks. (Mainly that panel->prepare is called when DSI host is ready to
> > allow the panel driver to send DSI commands and vice versa during
> > disable.)
> >
> > Tested on Pinephone Pro. Trace of the callbacks follows.
> >
> > Before:
> >
> > [ 1.253882] dw-mipi-dsi-rockchip ff960000.dsi: mode_set
> > [ 1.290732] panel-himax-hx8394 ff960000.dsi.0: prepare
> > [ 1.475576] dw-mipi-dsi-rockchip ff960000.dsi: enable
> > [ 1.475593] panel-himax-hx8394 ff960000.dsi.0: enable
> >
> > echo 2 > /sys/class/graphics/fb0/blank
> >
> > [ 13.722799] panel-himax-hx8394 ff960000.dsi.0: disable
> > [ 13.774502] dw-mipi-dsi-rockchip ff960000.dsi: post_disable
> > [ 13.774526] panel-himax-hx8394 ff960000.dsi.0: unprepare
> >
> > echo 0 > /sys/class/graphics/fb0/blank
> >
> > [ 17.735796] panel-himax-hx8394 ff960000.dsi.0: prepare
> > [ 17.923522] dw-mipi-dsi-rockchip ff960000.dsi: enable
> > [ 17.923540] panel-himax-hx8394 ff960000.dsi.0: enable
> > [ 17.944330] dw-mipi-dsi-rockchip ff960000.dsi: failed to write command FIFO
> > [ 17.944335] panel-himax-hx8394 ff960000.dsi.0: sending command 0xb9 failed: -110
> > [ 17.944340] panel-himax-hx8394 ff960000.dsi.0: Panel init sequence failed: -110
> >
> > echo 2 > /sys/class/graphics/fb0/blank
> >
> > [ 431.148583] panel-himax-hx8394 ff960000.dsi.0: disable
> > [ 431.169259] dw-mipi-dsi-rockchip ff960000.dsi: failed to write command FIFO
> > [ 431.169268] panel-himax-hx8394 ff960000.dsi.0: Failed to enter sleep mode: -110
> > [ 431.169282] dw-mipi-dsi-rockchip ff960000.dsi: post_disable
> > [ 431.169316] panel-himax-hx8394 ff960000.dsi.0: unprepare
> > [ 431.169357] pclk_mipi_dsi0 already disabled
> >
> > echo 0 > /sys/class/graphics/fb0/blank
> >
> > [ 432.796851] panel-himax-hx8394 ff960000.dsi.0: prepare
> > [ 432.981537] dw-mipi-dsi-rockchip ff960000.dsi: enable
> > [ 432.981568] panel-himax-hx8394 ff960000.dsi.0: enable
> > [ 433.002290] dw-mipi-dsi-rockchip ff960000.dsi: failed to write command FIFO
> > [ 433.002299] panel-himax-hx8394 ff960000.dsi.0: sending command 0xb9 failed: -110
> > [ 433.002312] panel-himax-hx8394 ff960000.dsi.0: Panel init sequence failed: -110
> >
> > -----------------------------------------------------------------------
> >
> > After:
> >
> > [ 1.248372] dw-mipi-dsi-rockchip ff960000.dsi: mode_set
> > [ 1.248704] dw-mipi-dsi-rockchip ff960000.dsi: pre_enable
> > [ 1.285377] panel-himax-hx8394 ff960000.dsi.0: prepare
> > [ 1.468392] dw-mipi-dsi-rockchip ff960000.dsi: enable
> > [ 1.468421] panel-himax-hx8394 ff960000.dsi.0: enable
> >
> > echo 2 > /sys/class/graphics/fb0/blank
> >
> > [ 16.210357] panel-himax-hx8394 ff960000.dsi.0: disable
> > [ 16.261315] dw-mipi-dsi-rockchip ff960000.dsi: post_disable
> > [ 16.261339] panel-himax-hx8394 ff960000.dsi.0: unprepare
> >
> > echo 0 > /sys/class/graphics/fb0/blank
> >
> > [ 19.161453] dw-mipi-dsi-rockchip ff960000.dsi: pre_enable
> > [ 19.197869] panel-himax-hx8394 ff960000.dsi.0: prepare
> > [ 19.382141] dw-mipi-dsi-rockchip ff960000.dsi: enable
> > [ 19.382158] panel-himax-hx8394 ff960000.dsi.0: enable
> >
> > Signed-off-by: Ondrej Jirman <megi@....cz>
>
> Nice cleanup and fix.
> Have you consider if this need a Fixes: ?
It might be useful, I'll hunt for some some useful base for a Fixes tag.
>
> > ---
> > drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 28 +++++++++++--------
> > 1 file changed, 16 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> > index b2efecf7d160..352c6829259a 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> > @@ -265,6 +265,7 @@ struct dw_mipi_dsi {
> > struct dw_mipi_dsi *master; /* dual-dsi master ptr */
> > struct dw_mipi_dsi *slave; /* dual-dsi slave ptr */
> >
> > + struct drm_display_mode mode;
> > const struct dw_mipi_dsi_plat_data *plat_data;
> > };
> >
> > @@ -332,6 +333,7 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
> > if (IS_ERR(bridge))
> > return PTR_ERR(bridge);
> >
> > + bridge->pre_enable_prev_first = true;
> > dsi->panel_bridge = bridge;
> >
> > drm_bridge_add(&dsi->bridge);
> > @@ -859,15 +861,6 @@ static void dw_mipi_dsi_bridge_post_atomic_disable(struct drm_bridge *bridge,
> > */
> > dw_mipi_dsi_set_mode(dsi, 0);
> >
> > - /*
> > - * TODO Only way found to call panel-bridge post_disable &
> > - * panel unprepare before the dsi "final" disable...
> > - * This needs to be fixed in the drm_bridge framework and the API
> > - * needs to be updated to manage our own call chains...
> > - */
> > - if (dsi->panel_bridge->funcs->post_disable)
> > - dsi->panel_bridge->funcs->post_disable(dsi->panel_bridge);
> > -
> > if (phy_ops->power_off)
> > phy_ops->power_off(dsi->plat_data->priv_data);
> >
> > @@ -942,15 +935,25 @@ static void dw_mipi_dsi_mode_set(struct dw_mipi_dsi *dsi,
> > phy_ops->power_on(dsi->plat_data->priv_data);
> > }
> >
> > +static void dw_mipi_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
> > + struct drm_bridge_state *old_bridge_state)
> > +{
> > + struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> > +
> > + /* Power up the dsi ctl into a command mode */
> > + dw_mipi_dsi_mode_set(dsi, &dsi->mode);
> > + if (dsi->slave)
> > + dw_mipi_dsi_mode_set(dsi->slave, &dsi->mode);
> > +}
> > +
> > static void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
> > const struct drm_display_mode *mode,
> > const struct drm_display_mode *adjusted_mode)
> > {
> > struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> >
> > - dw_mipi_dsi_mode_set(dsi, adjusted_mode);
> > - if (dsi->slave)
> > - dw_mipi_dsi_mode_set(dsi->slave, adjusted_mode);
> > + /* Store the display mode for later use in pre_enable callback */
> > + memcpy(&dsi->mode, adjusted_mode, sizeof(dsi->mode));
> > }
> Use drm_mode_copy here.
Ok.
> With this fixed:
>
> Reviewed-by: Sam Ravnborg <sam@...nborg.org>
thank you,
Ondrej
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