Re: i915_driver_irq_handler: irq 42: nobody cared

Daniel Vetter
2012-04-10T20:31:22Z

On Tue, Apr 10, 2012 at 09:52:40PM +0200, Jiri Slaby wrote:
> On 04/10/2012 08:34 PM, Jesse Barnes wrote:
> > On Tue, 10 Apr 2012 20:11:29 +0200 Jiri Slaby <jslaby@suse.cz>
> > wrote:
> >
> >> On 04/10/2012 06:26 PM, Jesse Barnes wrote:
> >>> So port hotplug is always reporting that port C has a hotplug
> >>> interrupt though... If you write 0x3 back to it does the
> >>> interrupt stop?
> >>
> >> I'm not sure I got it right. This doesn't help: ---
> >> a/drivers/gpu/drm/i915/i915_irq.c +++
> >> b/drivers/gpu/drm/i915/i915_irq.c @@ -1416,6 +1416,17 @@ static
> >> irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS) iir = new_iir;
> >> }
> >>
> >> + if (ret == IRQ_NONE) { + u32 hp =
> >> I915_READ(PORT_HOTPLUG_STAT); + if (hp) { +
> >> I915_WRITE(PORT_HOTPLUG_STAT, hp); +
> >> I915_READ(PORT_HOTPLUG_STAT); + } + +
> >> if (printk_ratelimit()) + printk(KERN_DEBUG
> >> "%s: %.8x\n", __func__, hp); + + }
> >>
> >> return ret; }
> >
> > Yeah that looks right, you still get 0x300?
>
> Yes.
>
> > You could try masking hotplug interrupts altogether.
>
> This doesn't help:
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2049,7 +2051,7 @@ static int i915_driver_irq_postinstall(struct
> drm_device *dev)
> I915_WRITE(IER, enable_mask);
> POSTING_READ(IER);
>
> - if (I915_HAS_HOTPLUG(dev)) {
> + if (0 && I915_HAS_HOTPLUG(dev)) {
> u32 hotplug_en = I915_READ(PORT_HOTPLUG_EN);
>
> /* Note HDMI and DP share bits */
>
>
> > Also, just to sanity check things, can you look at the output of
> > "lspci -s 02.0 -vvv -xxx" and see if the "INTx" field is + or -?
> > If it's +, then the interrupt is definitely coming from an un-acked
> > IRQ source on the gfx device. If it's INTx-, it means something in
> > one of the upper MSI layers isn't getting handled right.
>
> Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort-
> <TAbort- <MAbort- >SERR- <PERR- INTx-
>
> I tried 3.2 and 3.3. Although the spurious interrupts were always
> there, they occurred with frequency lower by a magnitude (15 vs. 300
> after X starts). So I bisected that and it lead to a commit which
> fixes bad tiling for me:
> http://cgit.freedesktop.org/~ickle/linux-2.6/commit/?h=for-jiri&id=79710e6ccabdac80c65cd13b944695ecc3e42a9d

Pipelined fencing is pretty much just broken and we'll completely rip it
out in 3.5. Does this also happen with 3.4-rc2?
-Daniel
--
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48