On Mon, Sep 11, 2023 at 03:44:06PM +0200, Greg Kroah-Hartman wrote:
>
> 6.1-stable review patch. If anyone has any objections, please let me know.
See patch message comment:
(But depends on functionality intorduced in Linux 6.3, so this patch will
not build on older kernels when applied to older stable branches.)
kind regards,
o.
> ------------------
>
> From: Ondrej Jirman <megi@xxxxxx>
>
> [ Upstream commit 05aa61334592adb230749ff465b103ee10e63936 ]
>
> 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
>
> (But depends on functionality intorduced in Linux 6.3, so this patch will
> not build on older kernels when applied to older stable branches.)
>
> Fixes: 46fc51546d44 ("drm/bridge/synopsys: Add MIPI DSI host controller bridge")
> Signed-off-by: Ondrej Jirman <megi@xxxxxx>
> Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
> Signed-off-by: Robert Foss <rfoss@xxxxxxxxxx>
> Link: https://patchwork.freedesktop.org/patch/msgid/20230617224915.1923630-1-megi@xxxxxx
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> 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 b2efecf7d1603..4291798bd70f5 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 */
> + drm_mode_copy(&dsi->mode, adjusted_mode);
> }
>
> static void dw_mipi_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
> @@ -1004,6 +1007,7 @@ static const struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
> .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> .atomic_reset = drm_atomic_helper_bridge_reset,
> + .atomic_pre_enable = dw_mipi_dsi_bridge_atomic_pre_enable,
> .atomic_enable = dw_mipi_dsi_bridge_atomic_enable,
> .atomic_post_disable = dw_mipi_dsi_bridge_post_atomic_disable,
> .mode_set = dw_mipi_dsi_bridge_mode_set,
> --
> 2.40.1
>
>
>
