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[104.57.184.186]) by smtp.gmail.com with ESMTPSA id 94sm1548656otw.41.2021.01.14.19.33.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Jan 2021 19:33:44 -0800 (PST) Date: Thu, 14 Jan 2021 21:33:43 -0600 From: Bjorn Andersson To: Dmitry Baryshkov Cc: dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, Daniel Vetter , David Airlie , Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Vinod Koul , Sam Ravnborg , Manivannan Sadhasivam Subject: Re: [PATCH 2/2] drm/bridge/lontium-lt9611uxc: move HPD notification out of IRQ handler Message-ID: References: <20201127092316.122246-1-dmitry.baryshkov@linaro.org> <20201127092316.122246-2-dmitry.baryshkov@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201127092316.122246-2-dmitry.baryshkov@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Fri 27 Nov 03:23 CST 2020, Dmitry Baryshkov wrote: > drm hotplug handling code (drm_client_dev_hotplug()) can wait on mutex, > thus delaying further lt9611uxc IRQ events processing. It was observed > occasionally during bootups, when drm_client_modeset_probe() was waiting > for EDID ready event, which was delayed because IRQ handler was stuck > trying to deliver hotplug event. > Move hotplug notifications from IRQ handler to separate work to be able > to process IRQ events without delays. > I see a couple of other drivers doing the same, and the patch looks good. Reviewed-by: Bjorn Andersson Regards, Bjorn > Signed-off-by: Dmitry Baryshkov > --- > drivers/gpu/drm/bridge/lontium-lt9611uxc.c | 30 +++++++++++++++++----- > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c > index b708700e182d..88630bc2921f 100644 > --- a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c > +++ b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > #include > > @@ -36,6 +37,7 @@ struct lt9611uxc { > struct mutex ocm_lock; > > struct wait_queue_head wq; > + struct work_struct work; > > struct device_node *dsi0_node; > struct device_node *dsi1_node; > @@ -52,6 +54,7 @@ struct lt9611uxc { > > bool hpd_supported; > bool edid_read; > + bool hdmi_connected; > uint8_t fw_version; > }; > > @@ -151,15 +154,26 @@ static irqreturn_t lt9611uxc_irq_thread_handler(int irq, void *dev_id) > } > > if (irq_status & BIT(1)) { > - if (lt9611uxc->connector.dev) > - drm_kms_helper_hotplug_event(lt9611uxc->connector.dev); > - else > - drm_bridge_hpd_notify(<9611uxc->bridge, !!(hpd_status & BIT(1))); > + lt9611uxc->hdmi_connected = !!(hpd_status & BIT(1)); > + schedule_work(<9611uxc->work); > } > > return IRQ_HANDLED; > } > > +void lt9611uxc_hpd_work(struct work_struct *work) > +{ > + struct lt9611uxc *lt9611uxc = container_of(work, struct lt9611uxc, work); > + > + if (lt9611uxc->connector.dev) > + drm_kms_helper_hotplug_event(lt9611uxc->connector.dev); > + else > + drm_bridge_hpd_notify(<9611uxc->bridge, > + lt9611uxc->hdmi_connected ? > + connector_status_connected : > + connector_status_disconnected); > +} > + > static void lt9611uxc_reset(struct lt9611uxc *lt9611uxc) > { > gpiod_set_value_cansleep(lt9611uxc->reset_gpio, 1); > @@ -447,7 +461,7 @@ static enum drm_connector_status lt9611uxc_bridge_detect(struct drm_bridge *brid > struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge); > unsigned int reg_val = 0; > int ret; > - int connected = 1; > + bool connected = true; > > if (lt9611uxc->hpd_supported) { > lt9611uxc_lock(lt9611uxc); > @@ -457,8 +471,9 @@ static enum drm_connector_status lt9611uxc_bridge_detect(struct drm_bridge *brid > if (ret) > dev_err(lt9611uxc->dev, "failed to read hpd status: %d\n", ret); > else > - connected = reg_val & BIT(1); > + connected = !!(reg_val & BIT(1)); > } > + lt9611uxc->hdmi_connected = connected; > > return connected ? connector_status_connected : > connector_status_disconnected; > @@ -931,6 +946,8 @@ static int lt9611uxc_probe(struct i2c_client *client, > lt9611uxc->fw_version = ret; > > init_waitqueue_head(<9611uxc->wq); > + INIT_WORK(<9611uxc->work, lt9611uxc_hpd_work); > + > ret = devm_request_threaded_irq(dev, client->irq, NULL, > lt9611uxc_irq_thread_handler, > IRQF_ONESHOT, "lt9611uxc", lt9611uxc); > @@ -967,6 +984,7 @@ static int lt9611uxc_remove(struct i2c_client *client) > struct lt9611uxc *lt9611uxc = i2c_get_clientdata(client); > > disable_irq(client->irq); > + flush_scheduled_work(); > lt9611uxc_audio_exit(lt9611uxc); > drm_bridge_remove(<9611uxc->bridge); > > -- > 2.29.2 >