[PATCH 2/2] nouveau: Acknowledge HPD irq in handler, not bottom half

[Andrew Lutomirski]

On Wed, Nov 10, 2010 at 5:10 PM, Ben Skeggs <bskeggs at redhat.com> wrote:
> On Wed, 2010-11-10 at 16:32 -0500, Andy Lutomirski wrote:
>> The old code generated an interrupt storm bad enough to completely
>> take down my system.
>>
>> This only fixes the bits that are defined nouveau_regs.h.  Newer hardware
>> uses another register that isn't described, and I don't have that hardware
>> to test.
> Thanks for looking at this.  I'll take a closer look at the problem
> today and see what I can come up with too, that'll work with the newer
> hardware too.

It should be as simple as adding an hpd1 field to the hpd_state and
making exactly the same change.  (It would be nice to put the register
definitions into nouveau_regs.h as well -- I didn't really want to
muck around with a bunch of magic numbers that I can't test.)

I tried writing 0xffffffff to the display IRQ control in the handler
to explicitly acknowledge the IRQ, but either I did it wrong or it had
no effect.

I imagine that this explains the unreproducible crashes I had on F13 as well.

--Andy

>
> Ben.
>>
>> Signed-off-by: Andy Lutomirski <luto at mit.edu>
>> Cc: <stable at kernel.org>
>> ---
>>  drivers/gpu/drm/nouveau/nouveau_drv.h  |    5 +++++
>>  drivers/gpu/drm/nouveau/nouveau_irq.c  |    1 +
>>  drivers/gpu/drm/nouveau/nv50_display.c |   17 +++++++++++++----
>>  3 files changed, 19 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
>> index b1be617..b6c62cc 100644
>> --- a/drivers/gpu/drm/nouveau/nouveau_drv.h
>> +++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
>> @@ -531,6 +531,11 @@ struct drm_nouveau_private {
>>       struct work_struct irq_work;
>>       struct work_struct hpd_work;
>>
>> +     struct {
>> +             spinlock_t lock;
>> +             uint32_t hpd0_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 794b0ee..b62a601 100644
>> --- a/drivers/gpu/drm/nouveau/nouveau_irq.c
>> +++ b/drivers/gpu/drm/nouveau/nouveau_irq.c
>> @@ -52,6 +52,7 @@ 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 83a7d27..0df08e3 100644
>> --- a/drivers/gpu/drm/nouveau/nv50_display.c
>> +++ b/drivers/gpu/drm/nouveau/nv50_display.c
>> @@ -1014,7 +1014,12 @@ nv50_display_irq_hotplug_bh(struct work_struct *work)
>>       uint32_t unplug_mask, plug_mask, change_mask;
>>       uint32_t hpd0, hpd1 = 0;
>>
>> -     hpd0 = nv_rd32(dev, NV50_PCONNECTOR_HOTPLUG_CTRL) & nv_rd32(dev, NV50_PCONNECTOR_HOTPLUG_INTR);
>> +     spin_lock_irq(&dev_priv->hpd_state.lock);
>> +     hpd0 = dev_priv->hpd_state.hpd0_bits;
>> +     dev_priv->hpd_state.hpd0_bits = 0;
>> +     spin_unlock_irq(&dev_priv->hpd_state.lock);
>> +
>> +     hpd0 &= nv_rd32(dev, NV50_PCONNECTOR_HOTPLUG_INTR);
>>       if (dev_priv->chipset >= 0x90)
>>               hpd1 = nv_rd32(dev, 0xe074) & nv_rd32(dev, 0xe070);
>>
>> @@ -1058,7 +1063,6 @@ nv50_display_irq_hotplug_bh(struct work_struct *work)
>>                       helper->dpms(connector->encoder, DRM_MODE_DPMS_OFF);
>>       }
>>
>> -     nv_wr32(dev, NV50_PCONNECTOR_HOTPLUG_CTRL, nv_rd32(dev, NV50_PCONNECTOR_HOTPLUG_CTRL));
>>       if (dev_priv->chipset >= 0x90)
>>               nv_wr32(dev, 0xe074, nv_rd32(dev, 0xe074));
>>
>> @@ -1072,8 +1076,13 @@ 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 = nv_rd32(dev, NV50_PCONNECTOR_HOTPLUG_CTRL);
>> +             nv_wr32(dev, NV50_PCONNECTOR_HOTPLUG_CTRL, hpd0_bits);
>> +             spin_lock(&dev_priv->hpd_state.lock);
>> +             dev_priv->hpd_state.hpd0_bits |= hpd0_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) {
>
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>