drm/msm/dsi: Queue HPD helper work in attach/detach callbacks

The msm/dsi host drivers calls drm_helper_hpd_irq_event in the
mipi_dsi_host attach/detatch callbacks.

mipi_dsi_attach()/mipi_dsi_detach() from a panel/bridge
driver could be called from a context where the drm_device's
mode_config.mutex is already held, resulting in a deadlock.
Queue it as work instead.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index f05ed0e..6f24002 100644 (file)
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -139,6 +139,7 @@ struct msm_dsi_host {
 
        u32 err_work_state;
        struct work_struct err_work;
+       struct work_struct hpd_work;
        struct workqueue_struct *workqueue;
 
        /* DSI 6G TX buffer*/
@@ -1294,6 +1295,14 @@ static void dsi_sw_reset_restore(struct msm_dsi_host *msm_host)
        wmb();  /* make sure dsi controller enabled again */
 }
 
+static void dsi_hpd_worker(struct work_struct *work)
+{
+       struct msm_dsi_host *msm_host =
+               container_of(work, struct msm_dsi_host, hpd_work);
+
+       drm_helper_hpd_irq_event(msm_host->dev);
+}
+
 static void dsi_err_worker(struct work_struct *work)
 {
        struct msm_dsi_host *msm_host =
@@ -1480,7 +1489,7 @@ static int dsi_host_attach(struct mipi_dsi_host *host,
 
        DBG("id=%d", msm_host->id);
        if (msm_host->dev)
-               drm_helper_hpd_irq_event(msm_host->dev);
+               queue_work(msm_host->workqueue, &msm_host->hpd_work);
 
        return 0;
 }
@@ -1494,7 +1503,7 @@ static int dsi_host_detach(struct mipi_dsi_host *host,
 
        DBG("id=%d", msm_host->id);
        if (msm_host->dev)
-               drm_helper_hpd_irq_event(msm_host->dev);
+               queue_work(msm_host->workqueue, &msm_host->hpd_work);
 
        return 0;
 }
@@ -1748,6 +1757,7 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
        /* setup workqueue */
        msm_host->workqueue = alloc_ordered_workqueue("dsi_drm_work", 0);
        INIT_WORK(&msm_host->err_work, dsi_err_worker);
+       INIT_WORK(&msm_host->hpd_work, dsi_hpd_worker);
 
        msm_dsi->host = &msm_host->base;
        msm_dsi->id = msm_host->id;