ALSA: x86: Fix sleep-in-atomic via i915 notification

i915 notification is executed in a spinlock, thus it must not sleep;
i.e. we can't use kmalloc with GFP_KERNEL or such.

For making it working properly, move the notification handler in a
work, and handle it gracefully.  We have already such a work, and it
was used just at the start.  This can be re-used in a more generic
hotplug handling.

Also, the patch adds the proper call of cancel_work_sync() to the
destructor.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/x86/intel_hdmi_audio.c b/sound/x86/intel_hdmi_audio.c
index 28eb980d2d2e700f979566fe4172dbf93c3d070e..ab199b5deaa5dee5d4bdc4c1fb1c2b528a3901f2 100644 (file)
--- a/sound/x86/intel_hdmi_audio.c
+++ b/sound/x86/intel_hdmi_audio.c
@@ -1857,14 +1857,6 @@ static struct snd_kcontrol_new had_control_iec958 = {
        .put =          had_iec958_put
 };
 
-static void _had_wq(struct work_struct *work)
-{
-       struct snd_intelhad *ctx =
-               container_of(work, struct snd_intelhad, hdmi_audio_wq);
-
-       had_process_hot_plug(ctx);
-}
-
 static irqreturn_t display_pipe_interrupt_handler(int irq, void *dev_id)
 {
        struct snd_intelhad *ctx = dev_id;
@@ -1889,21 +1881,28 @@ static irqreturn_t display_pipe_interrupt_handler(int irq, void *dev_id)
 static void notify_audio_lpe(struct platform_device *pdev)
 {
        struct snd_intelhad *ctx = platform_get_drvdata(pdev);
-       struct intel_hdmi_lpe_audio_pdata *pdata = pdev->dev.platform_data;
-
-       if (pdata->hdmi_connected != true) {
 
-               dev_dbg(&pdev->dev, "%s: Event: HAD_NOTIFY_HOT_UNPLUG\n",
-                       __func__);
+       schedule_work(&ctx->hdmi_audio_wq);
+}
 
-               if (ctx->state == hdmi_connector_status_connected) {
+static void had_audio_wq(struct work_struct *work)
+{
+       struct snd_intelhad *ctx =
+               container_of(work, struct snd_intelhad, hdmi_audio_wq);
+       struct intel_hdmi_lpe_audio_pdata *pdata = ctx->dev->platform_data;
 
-                       ctx->state = hdmi_connector_status_disconnected;
+       if (!pdata->hdmi_connected) {
+               dev_dbg(ctx->dev, "%s: Event: HAD_NOTIFY_HOT_UNPLUG\n",
+                       __func__);
 
-                       had_process_hot_unplug(ctx);
-               } else
-                       dev_dbg(&pdev->dev, "%s: Already Unplugged!\n",
+               if (ctx->state != hdmi_connector_status_connected) {
+                       dev_dbg(ctx->dev, "%s: Already Unplugged!\n",
                                __func__);
+                       return;
+               }
+
+               ctx->state = hdmi_connector_status_disconnected;
+               had_process_hot_unplug(ctx);
 
        } else {
                struct intel_hdmi_lpe_audio_eld *eld = &pdata->eld;
@@ -1919,7 +1918,7 @@ static void notify_audio_lpe(struct platform_device *pdev)
                        ctx->had_config_offset = AUDIO_HDMI_CONFIG_C;
                        break;
                default:
-                       dev_dbg(&pdev->dev, "Invalid pipe %d\n",
+                       dev_dbg(ctx->dev, "Invalid pipe %d\n",
                                eld->pipe_id);
                        break;
                }
@@ -1930,7 +1929,7 @@ static void notify_audio_lpe(struct platform_device *pdev)
 
                ctx->state = hdmi_connector_status_connected;
 
-               dev_dbg(&pdev->dev, "%s: HAD_NOTIFY_ELD : port = %d, tmds = %d\n",
+               dev_dbg(ctx->dev, "%s: HAD_NOTIFY_ELD : port = %d, tmds = %d\n",
                        __func__, eld->port_id, pdata->tmds_clock_speed);
 
                if (pdata->tmds_clock_speed) {
@@ -1950,6 +1949,8 @@ static void hdmi_lpe_audio_free(struct snd_card *card)
 {
        struct snd_intelhad *ctx = card->private_data;
 
+       cancel_work_sync(&ctx->hdmi_audio_wq);
+
        if (ctx->mmio_start)
                iounmap(ctx->mmio_start);
        if (ctx->irq >= 0)
@@ -2013,7 +2014,7 @@ static int hdmi_lpe_audio_probe(struct platform_device *pdev)
 
        ctx->irq = -1;
        ctx->tmds_clock_speed = DIS_SAMPLE_RATE_148_5;
-       INIT_WORK(&ctx->hdmi_audio_wq, _had_wq);
+       INIT_WORK(&ctx->hdmi_audio_wq, had_audio_wq);
        ctx->state = hdmi_connector_status_disconnected;
 
        card->private_free = hdmi_lpe_audio_free;
@@ -2086,17 +2087,13 @@ static int hdmi_lpe_audio_probe(struct platform_device *pdev)
 
        spin_lock_irqsave(&pdata->lpe_audio_slock, flags);
        pdata->notify_audio_lpe = notify_audio_lpe;
-       if (pdata->notify_pending) {
-
-               dev_dbg(&pdev->dev, "%s: handle pending notification\n", __func__);
-               notify_audio_lpe(pdev);
-               pdata->notify_pending = false;
-       }
+       pdata->notify_pending = false;
        spin_unlock_irqrestore(&pdata->lpe_audio_slock, flags);
 
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);
 
+       dev_dbg(&pdev->dev, "%s: handle pending notification\n", __func__);
        schedule_work(&ctx->hdmi_audio_wq);
 
        return 0;