Re: [PATCH] drm/msm/dp: do not initialize phy until plugin interrupt received

From: Bjorn Andersson
Date: Fri Nov 05 2021 - 13:47:04 EST

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In reply to: Kuogee Hsieh: "[PATCH] drm/msm/dp: do not initialize phy until plugin interrupt received"
Next in thread: Kuogee Hsieh: "Re: [PATCH] drm/msm/dp: do not initialize phy until plugin interrupt received"
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On Fri 05 Nov 10:28 PDT 2021, Kuogee Hsieh wrote:

> From: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
>
> Combo phy supports both USB and DP simultaneously. There may has a
> possible conflict during phy initialization phase between USB and
> DP driver which may cause USB phy timeout when USB tries to power
> up its phy. This patch has the DP driver not initialize its phy
> during DP driver initialization phase. Instead DP driver only enable
> required regulators and clocks so that it is able to receive HPD
> interrupts after completion of initialization phase. DP driver will
> initialize its phy when HPD plug-in interrupt received.

Is this a hardware requirement, or is this a issue with the current
implementation of the QMP combo phy driver? We should not hack up the DP
driver to circumvent the latter.

Also, I don't suppose there's anything here that prevents the HPD to
come before the USB PHY is powered up? Even though that seems less
likely in practice...

> This patch also provides a positive side effects which balance regulator
> enable count since regulator only enabled at initialize phase and resume
> and disabled at followed suspend.
>

Is this something that needs to be fixed separately, so that it can be
backported to stable kernels?

Regards,
Bjorn

> Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/dp/dp_ctrl.c | 97 ++++++++++++++++++++++---------------
> drivers/gpu/drm/msm/dp/dp_ctrl.h | 9 ++--
> drivers/gpu/drm/msm/dp/dp_display.c | 71 ++++++++++++++++++++-------
> 3 files changed, 119 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index 7ec155d..e0e5dc9 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -1364,7 +1364,41 @@ static int dp_ctrl_enable_stream_clocks(struct dp_ctrl_private *ctrl)
> return ret;
> }
>
> -int dp_ctrl_host_init(struct dp_ctrl *dp_ctrl, bool flip, bool reset)
> +void dp_ctrl_irq_enable(struct dp_ctrl *dp_ctrl, bool flip)
> +{
> + struct dp_ctrl_private *ctrl;
> +
> + if (!dp_ctrl) {
> + DRM_ERROR("Invalid input data\n");
> + return;
> + }
> +
> + ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
> +
> + ctrl->dp_ctrl.orientation = flip;
> +
> + dp_catalog_ctrl_reset(ctrl->catalog);
> +
> + dp_catalog_ctrl_enable_irq(ctrl->catalog, true);
> +}
> +
> +void dp_ctrl_irq_disable(struct dp_ctrl *dp_ctrl)
> +{
> + struct dp_ctrl_private *ctrl;
> +
> + if (!dp_ctrl) {
> + DRM_ERROR("Invalid input data\n");
> + return;
> + }
> +
> + ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
> +
> + dp_catalog_ctrl_reset(ctrl->catalog);
> +
> + dp_catalog_ctrl_enable_irq(ctrl->catalog, false);
> +}
> +
> +void dp_ctrl_phy_init(struct dp_ctrl *dp_ctrl)
> {
> struct dp_ctrl_private *ctrl;
> struct dp_io *dp_io;
> @@ -1372,34 +1406,24 @@ int dp_ctrl_host_init(struct dp_ctrl *dp_ctrl, bool flip, bool reset)
>
> if (!dp_ctrl) {
> DRM_ERROR("Invalid input data\n");
> - return -EINVAL;
> + return;
> }
>
> ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
> dp_io = &ctrl->parser->io;
> phy = dp_io->phy;
>
> - ctrl->dp_ctrl.orientation = flip;
> -
> - if (reset)
> - dp_catalog_ctrl_reset(ctrl->catalog);
> + DRM_DEBUG_DP("Before, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
>
> - DRM_DEBUG_DP("flip=%d\n", flip);
> dp_catalog_ctrl_phy_reset(ctrl->catalog);
> phy_init(phy);
> - dp_catalog_ctrl_enable_irq(ctrl->catalog, true);
>
> - return 0;
> + DRM_DEBUG_DP("After, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
> }
>
> -/**
> - * dp_ctrl_host_deinit() - Uninitialize DP controller
> - * @dp_ctrl: Display Port Driver data
> - *
> - * Perform required steps to uninitialize DP controller
> - * and its resources.
> - */
> -void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl)
> +void dp_ctrl_phy_exit(struct dp_ctrl *dp_ctrl)
> {
> struct dp_ctrl_private *ctrl;
> struct dp_io *dp_io;
> @@ -1414,10 +1438,14 @@ void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl)
> dp_io = &ctrl->parser->io;
> phy = dp_io->phy;
>
> - dp_catalog_ctrl_enable_irq(ctrl->catalog, false);
> + DRM_DEBUG_DP("Before, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
> +
> + dp_catalog_ctrl_phy_reset(ctrl->catalog);
> phy_exit(phy);
>
> - DRM_DEBUG_DP("Host deinitialized successfully\n");
> + DRM_DEBUG_DP("After, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
> }
>
> static bool dp_ctrl_use_fixed_nvid(struct dp_ctrl_private *ctrl)
> @@ -1895,8 +1923,14 @@ int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl)
> return ret;
> }
>
> + DRM_DEBUG_DP("Before, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
> +
> phy_power_off(phy);
>
> + DRM_DEBUG_DP("After, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
> +
> /* aux channel down, reinit phy */
> phy_exit(phy);
> phy_init(phy);
> @@ -1905,23 +1939,6 @@ int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl)
> return ret;
> }
>
> -void dp_ctrl_off_phy(struct dp_ctrl *dp_ctrl)
> -{
> - struct dp_ctrl_private *ctrl;
> - struct dp_io *dp_io;
> - struct phy *phy;
> -
> - ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
> - dp_io = &ctrl->parser->io;
> - phy = dp_io->phy;
> -
> - dp_catalog_ctrl_reset(ctrl->catalog);
> -
> - phy_exit(phy);
> -
> - DRM_DEBUG_DP("DP off phy done\n");
> -}
> -
> int dp_ctrl_off(struct dp_ctrl *dp_ctrl)
> {
> struct dp_ctrl_private *ctrl;
> @@ -1949,10 +1966,14 @@ int dp_ctrl_off(struct dp_ctrl *dp_ctrl)
> DRM_ERROR("Failed to disable link clocks. ret=%d\n", ret);
> }
>
> + DRM_DEBUG_DP("Before, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
> +
> phy_power_off(phy);
> - phy_exit(phy);
>
> - DRM_DEBUG_DP("DP off done\n");
> + DRM_DEBUG_DP("After, phy=%x init_count=%d power_on=%d\n",
> + (u32)(uintptr_t)phy, phy->init_count, phy->power_count);
> +
> return ret;
> }
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> index 2363a2d..c1e4b1b 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> @@ -19,12 +19,9 @@ struct dp_ctrl {
> u32 pixel_rate;
> };
>
> -int dp_ctrl_host_init(struct dp_ctrl *dp_ctrl, bool flip, bool reset);
> -void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl);
> int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl);
> int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl);
> int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl);
> -void dp_ctrl_off_phy(struct dp_ctrl *dp_ctrl);
> int dp_ctrl_off(struct dp_ctrl *dp_ctrl);
> void dp_ctrl_push_idle(struct dp_ctrl *dp_ctrl);
> void dp_ctrl_isr(struct dp_ctrl *dp_ctrl);
> @@ -34,4 +31,10 @@ struct dp_ctrl *dp_ctrl_get(struct device *dev, struct dp_link *link,
> struct dp_power *power, struct dp_catalog *catalog,
> struct dp_parser *parser);
>
> +void dp_ctrl_irq_enable(struct dp_ctrl *dp_ctrl, bool flip);
> +void dp_ctrl_irq_disable(struct dp_ctrl *dp_ctrl);
> +void dp_ctrl_phy_init(struct dp_ctrl *dp_ctrl);
> +void dp_ctrl_phy_exit(struct dp_ctrl *dp_ctrl);
> +void dp_ctrl_irq_phy_exit(struct dp_ctrl *dp_ctrl);
> +
> #endif /* _DP_CTRL_H_ */
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index e41dd40..17d2d5c 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -84,6 +84,7 @@ struct dp_display_private {
>
> /* state variables */
> bool core_initialized;
> + bool phy_initialized;
> bool hpd_irq_on;
> bool audio_supported;
>
> @@ -387,7 +388,7 @@ static int dp_display_process_hpd_high(struct dp_display_private *dp)
> return rc;
> }
>
> -static void dp_display_host_init(struct dp_display_private *dp, int reset)
> +static void dp_display_host_init(struct dp_display_private *dp)
> {
> bool flip = false;
>
> @@ -400,12 +401,37 @@ static void dp_display_host_init(struct dp_display_private *dp, int reset)
> if (dp->usbpd->orientation == ORIENTATION_CC2)
> flip = true;
>
> - dp_power_init(dp->power, flip);
> - dp_ctrl_host_init(dp->ctrl, flip, reset);
> + dp_power_init(dp->power, false);
> + dp_ctrl_irq_enable(dp->ctrl, flip);
> +
> + if (dp->dp_display.connector_type == DRM_MODE_CONNECTOR_eDP)
> + dp_ctrl_phy_init(dp->ctrl);
> +
> dp_aux_init(dp->aux);
> dp->core_initialized = true;
> }
>
> +static void dp_display_host_phy_init(struct dp_display_private *dp)
> +{
> + DRM_DEBUG_DP("core_init=%d phy_init=%d\n",
> + dp->core_initialized, dp->phy_initialized);
> + if (dp->phy_initialized == false) {
> + dp_ctrl_phy_init(dp->ctrl);
> + dp->phy_initialized = true;
> + }
> +}
> +
> +static void dp_display_host_phy_exit(struct dp_display_private *dp)
> +{
> + DRM_DEBUG_DP("core_init=%d phy_init=%d\n",
> + dp->core_initialized, dp->phy_initialized);
> +
> + if (dp->phy_initialized == true) {
> + dp_ctrl_phy_exit(dp->ctrl);
> + dp->phy_initialized = false;
> + }
> +}
> +
> static void dp_display_host_deinit(struct dp_display_private *dp)
> {
> if (!dp->core_initialized) {
> @@ -413,7 +439,7 @@ static void dp_display_host_deinit(struct dp_display_private *dp)
> return;
> }
>
> - dp_ctrl_host_deinit(dp->ctrl);
> + dp_ctrl_irq_disable(dp->ctrl);
> dp_aux_deinit(dp->aux);
> dp_power_deinit(dp->power);
>
> @@ -424,7 +450,7 @@ static int dp_display_usbpd_configure_cb(struct device *dev)
> {
> struct dp_display_private *dp = dev_get_dp_display_private(dev);
>
> - dp_display_host_init(dp, true);
> + dp_display_host_phy_init(dp);
>
> return dp_display_process_hpd_high(dp);
> }
> @@ -551,7 +577,7 @@ static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
> dp->hpd_state = ST_DISCONNECTED;
>
> if (ret == -ECONNRESET) { /* cable unplugged */
> - dp->core_initialized = false;
> + dp->phy_initialized = false;
> }
>
> } else {
> @@ -623,9 +649,8 @@ static int dp_hpd_unplug_handle(struct dp_display_private *dp, u32 data)
> if (state == ST_DISCONNECTED) {
> /* triggered by irq_hdp with sink_count = 0 */
> if (dp->link->sink_count == 0) {
> - dp_ctrl_off_phy(dp->ctrl);
> + dp_display_host_phy_exit(dp);
> hpd->hpd_high = 0;
> - dp->core_initialized = false;
> }
> mutex_unlock(&dp->event_mutex);
> return 0;
> @@ -716,7 +741,7 @@ static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
>
> ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
> if (ret == -ECONNRESET) { /* cable unplugged */
> - dp->core_initialized = false;
> + dp->phy_initialized = false;
> }
> DRM_DEBUG_DP("hpd_state=%d\n", state);
>
> @@ -918,12 +943,19 @@ static int dp_display_disable(struct dp_display_private *dp, u32 data)
>
> dp_display->audio_enabled = false;
>
> - /* triggered by irq_hpd with sink_count = 0 */
> if (dp->link->sink_count == 0) {
> + /*
> + * irq_hpd with sink_count = 0
> + * hdmi unplugged out of dongle
> + */
> dp_ctrl_off_link_stream(dp->ctrl);
> } else {
> + /*
> + * unplugged interrupt
> + * dongle unplugged out of DUT
> + */
> dp_ctrl_off(dp->ctrl);
> - dp->core_initialized = false;
> + dp_display_host_phy_exit(dp);
> }
>
> dp_power_panel_on(dp->power, false);
> @@ -1059,7 +1091,7 @@ void msm_dp_snapshot(struct msm_disp_state *disp_state, struct msm_dp *dp)
> static void dp_display_config_hpd(struct dp_display_private *dp)
> {
>
> - dp_display_host_init(dp, true);
> + dp_display_host_init(dp);
> dp_catalog_ctrl_hpd_config(dp->catalog);
>
> /* Enable interrupt first time
> @@ -1338,7 +1370,7 @@ static int dp_pm_resume(struct device *dev)
> dp->hpd_state = ST_DISCONNECTED;
>
> /* turn on dp ctrl/phy */
> - dp_display_host_init(dp, true);
> + dp_display_host_init(dp);
>
> dp_catalog_ctrl_hpd_config(dp->catalog);
>
> @@ -1346,12 +1378,15 @@ static int dp_pm_resume(struct device *dev)
> * set sink to normal operation mode -- D0
> * before dpcd read
> */
> - dp_link_psm_config(dp->link, &dp->panel->link_info, false);
> -
> if (dp_catalog_link_is_connected(dp->catalog)) {
> + dp_display_host_phy_init(dp);
> +
> + dp_link_psm_config(dp->link, &dp->panel->link_info, false);
> sink_count = drm_dp_read_sink_count(dp->aux);
> if (sink_count < 0)
> sink_count = 0;
> +
> + dp_display_host_phy_exit(dp);
> }
>
> dp->link->sink_count = sink_count;
> @@ -1399,6 +1434,8 @@ static int dp_pm_suspend(struct device *dev)
> dp_display_host_deinit(dp);
> }
>
> + dp_display_host_phy_exit(dp);
> +
> dp->hpd_state = ST_SUSPENDED;
>
> /* host_init will be called at pm_resume */
> @@ -1473,7 +1510,7 @@ void msm_dp_irq_postinstall(struct msm_dp *dp_display)
> enable_irq(dp->irq);
> dp_hpd_connect(dp->usbpd, true);
> } else {
> - dp_add_event(dp, EV_HPD_INIT_SETUP, 0, dp->id * 10);
> + dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 0);
> }
> }
>
> @@ -1567,7 +1604,7 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder)
> state = dp_display->hpd_state;
>
> if (state == ST_DISPLAY_OFF)
> - dp_display_host_init(dp_display, true);
> + dp_display_host_phy_init(dp_display);
>
> dp_display_enable(dp_display, 0);
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>

Next message: Mauro Carvalho Chehab: "[PATCH 7/8] media: atomisp: add return codes for pipeline config functions"
Previous message: manafm: "Re: [PATCH] drivers: thermal: Reset previous low and high trip during thermal zone init"
In reply to: Kuogee Hsieh: "[PATCH] drm/msm/dp: do not initialize phy until plugin interrupt received"
Next in thread: Kuogee Hsieh: "Re: [PATCH] drm/msm/dp: do not initialize phy until plugin interrupt received"
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