nouveau: Acknowledge HPD irq in handler, not bottom half

The old code generated an interrupt storm bad enough to completely
take down my system.

Signed-off-by: Andy Lutomirski <luto@mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index 10a8d4e78e583d49f7818792d02b46ebf8eeabc0..1c7db64c03bf03b45070939f16bc5a0092820ba0 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -584,6 +584,12 @@ struct drm_nouveau_private {
        struct work_struct irq_work;
        struct work_struct hpd_work;
 
+       struct {
+               spinlock_t lock;
+               uint32_t hpd0_bits;
+               uint32_t hpd1_bits;
+       } hpd_state;
+
        struct list_head vbl_waiting;
 
        struct {

diff --git a/drivers/gpu/drm/nouveau/nouveau_irq.c b/drivers/gpu/drm/nouveau/nouveau_irq.c
index e2f2d59be3ead072fd9960d71add40746ce48d7a..7bfd9e6c9d67194b298047d7670a54a996c16750 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_irq.c
+++ b/drivers/gpu/drm/nouveau/nouveau_irq.c
@@ -60,6 +60,7 @@ nouveau_irq_preinstall(struct drm_device *dev)
        if (dev_priv->card_type >= NV_50) {
                INIT_WORK(&dev_priv->irq_work, nv50_display_irq_handler_bh);
                INIT_WORK(&dev_priv->hpd_work, nv50_display_irq_hotplug_bh);
+               spin_lock_init(&dev_priv->hpd_state.lock);
                INIT_LIST_HEAD(&dev_priv->vbl_waiting);
        }
 }

diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index 55c9663ef2bf8ddd4df2cf15b452daed66abc583..f624c611ddeaf39cb1c46010d7da30e4461c35ad 100644 (file)
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -1032,11 +1032,18 @@ nv50_display_irq_hotplug_bh(struct work_struct *work)
        struct drm_connector *connector;
        const uint32_t gpio_reg[4] = { 0xe104, 0xe108, 0xe280, 0xe284 };
        uint32_t unplug_mask, plug_mask, change_mask;
-       uint32_t hpd0, hpd1 = 0;
+       uint32_t hpd0, hpd1;
 
-       hpd0 = nv_rd32(dev, 0xe054) & nv_rd32(dev, 0xe050);
+       spin_lock_irq(&dev_priv->hpd_state.lock);
+       hpd0 = dev_priv->hpd_state.hpd0_bits;
+       dev_priv->hpd_state.hpd0_bits = 0;
+       hpd1 = dev_priv->hpd_state.hpd1_bits;
+       dev_priv->hpd_state.hpd1_bits = 0;
+       spin_unlock_irq(&dev_priv->hpd_state.lock);
+
+       hpd0 &= nv_rd32(dev, 0xe050);
        if (dev_priv->chipset >= 0x90)
-               hpd1 = nv_rd32(dev, 0xe074) & nv_rd32(dev, 0xe070);
+               hpd1 &= nv_rd32(dev, 0xe070);
 
        plug_mask   = (hpd0 & 0x0000ffff) | (hpd1 << 16);
        unplug_mask = (hpd0 >> 16) | (hpd1 & 0xffff0000);
@@ -1078,10 +1085,6 @@ nv50_display_irq_hotplug_bh(struct work_struct *work)
                        helper->dpms(connector->encoder, DRM_MODE_DPMS_OFF);
        }
 
-       nv_wr32(dev, 0xe054, nv_rd32(dev, 0xe054));
-       if (dev_priv->chipset >= 0x90)
-               nv_wr32(dev, 0xe074, nv_rd32(dev, 0xe074));
-
        drm_helper_hpd_irq_event(dev);
 }
 
@@ -1092,8 +1095,22 @@ nv50_display_irq_handler(struct drm_device *dev)
        uint32_t delayed = 0;
 
        if (nv_rd32(dev, NV50_PMC_INTR_0) & NV50_PMC_INTR_0_HOTPLUG) {
-               if (!work_pending(&dev_priv->hpd_work))
-                       queue_work(dev_priv->wq, &dev_priv->hpd_work);
+               uint32_t hpd0_bits, hpd1_bits = 0;
+
+               hpd0_bits = nv_rd32(dev, 0xe054);
+               nv_wr32(dev, 0xe054, hpd0_bits);
+
+               if (dev_priv->chipset >= 0x90) {
+                       hpd1_bits = nv_rd32(dev, 0xe074);
+                       nv_wr32(dev, 0xe074, hpd1_bits);
+               }
+
+               spin_lock(&dev_priv->hpd_state.lock);
+               dev_priv->hpd_state.hpd0_bits |= hpd0_bits;
+               dev_priv->hpd_state.hpd1_bits |= hpd1_bits;
+               spin_unlock(&dev_priv->hpd_state.lock);
+
+               queue_work(dev_priv->wq, &dev_priv->hpd_work);
        }
 
        while (nv_rd32(dev, NV50_PMC_INTR_0) & NV50_PMC_INTR_0_DISPLAY) {