[Intel-gfx] [PATCH] Manage PIPESTAT pending interrupt values to unblock vblank interrupts

[Steven J Newbury]

On Fri, 2008-11-07 at 20:45 +0000, Steven J Newbury wrote:
> On Fri, 2008-11-07 at 11:11 -0800, Eric Anholt wrote:
> > On Fri, 2008-11-07 at 14:01 +0000, Steven J Newbury wrote:

> > > I'm on 965GM and I'm having a serious interrupt problem since this patch
> > > went into for-review:
> > > 
> > > Nov  7 04:20:22 infinity irq 16: nobody cared (try booting with the
> > > "irqpoll" option)
> > > Nov  7 04:20:22 infinity Pid: 0, comm: swapper Not tainted
> > > 2.6.28-rc3-00236-g1d7eff8 #23
> > > Nov  7 04:20:22 infinity Call Trace:
> > > Nov  7 04:20:22 infinity <IRQ>  [<ffffffff80491a25>] ?
> > > i915_driver_irq_handler+0x53/0x186
> > > Nov  7 04:20:22 infinity [<ffffffff80270b55>] __report_bad_irq+0x3d/0x8c
> > > Nov  7 04:20:22 infinity [<ffffffff80270cb7>] note_interrupt+0x113/0x178
> > > Nov  7 04:20:22 infinity [<ffffffff802713db>] handle_fasteoi_irq
> > > +0x99/0xc3
> > > Nov  7 04:20:22 infinity [<ffffffff8020ee5f>] do_IRQ+0x9c/0x11d
> > > Nov  7 04:20:22 infinity [<ffffffff8020c826>] ret_from_intr+0x0/0xa
> > > Nov  7 04:20:22 infinity <EOI>  [<ffffffff804572c0>] ?
> > > acpi_idle_enter_simple+0x175/0x1a8
> > > Nov  7 04:20:22 infinity [<ffffffff804572b6>] ? acpi_idle_enter_simple
> > > +0x16b/0x1a8
> > > Nov  7 04:20:22 infinity [<ffffffff8052af56>] ? cpuidle_idle_call
> > > +0xa6/0xe0
> > > Nov  7 04:20:22 infinity [<ffffffff8020b47a>] ? cpu_idle+0x4c/0xb0
> > > Nov  7 04:20:22 infinity [<ffffffff80614551>] ? rest_init+0x75/0x77
> > > Nov  7 04:20:22 infinity handlers:
> > > Nov  7 04:20:22 infinity [<ffffffff804919d2>] (i915_driver_irq_handler
> > > +0x0/0x186)
> > > Nov  7 04:20:22 infinity Disabling IRQ #16
> > > 
> > > This happens after a random amount of time in X, athough never very
> > > long.  From this point on there are no interrupts generated unless I
> > > switch vts away from X and back again.
I'm wrong here.  Switching vts only "fixes" the second problem below.

>   This gets interrupts working
> > > again for a short while.
> > 
> > Can you get /proc/dri/0/i915_gem_interrupt from before and just after
> > the problem occurs?
> > 
> I'll fire up a for-review kernel and see what it says.

Before X:

Interrupt enable:    00000000
Interrupt identity:  00000000
Interrupt mask:      fffedfff
Pipe A stat:         00000203
Pipe B stat:         80000206
Interrupts received: 0
Current sequence:    0
Waiter sequence:     0
IRQ sequence:        0

After X has started:

Interrupt enable:    00000051
Interrupt identity:  00000002
Interrupt mask:      fffedfac
Pipe A stat:         00020204
Pipe B stat:         00000206
Interrupts received: 1327
Current sequence:    1742
Waiter sequence:     0
IRQ sequence:        1738

Interrupt enable:    00000051
Interrupt identity:  00000002
Interrupt mask:      fffedfac
Pipe A stat:         00020204
Pipe B stat:         00000206
Interrupts received: 33424
Current sequence:    43154
Waiter sequence:     0
IRQ sequence:        43132

Interrupt enable:    00000051
Interrupt identity:  00000002
Interrupt mask:      fffedfac
Pipe A stat:         00020204
Pipe B stat:         00020000
Interrupts received: 42250
Current sequence:    58442
Waiter sequence:     0
IRQ sequence:        58434
____

After interrupt failure:

Interrupt enable:    00000051
Interrupt identity:  00000000
Interrupt mask:      fffedfac
Pipe A stat:         00020204
Pipe B stat:         00000206
Interrupts received: 200097
Current sequence:    96282
Waiter sequence:     0
IRQ sequence:        96282

Output of 'cat /proc/interrupts' :
           CPU0       CPU1       
  0:     309831     301848   IO-APIC-edge      timer
  1:        964       1747   IO-APIC-edge      i8042
  4:          1          1   IO-APIC-edge    
  8:          1          0   IO-APIC-edge      rtc0
  9:          0          1   IO-APIC-fasteoi   acpi
 12:      11555      16280   IO-APIC-edge      i8042
 14:          0          0   IO-APIC-edge      ata_piix
 15:          0          0   IO-APIC-edge      ata_piix
 16:      99522     100479   IO-APIC-fasteoi   i915 at pci:0000:00:02.0
 19:          6          9   IO-APIC-fasteoi   yenta, firewire_ohci
 20:         75         63   IO-APIC-fasteoi   uhci_hcd:usb1,
uhci_hcd:usb3, ehci_hcd:usb7
 21:        204        216   IO-APIC-fasteoi   uhci_hcd:usb2,
uhci_hcd:usb4, HDA Intel
 22:        352        644   IO-APIC-fasteoi   uhci_hcd:usb5,
ehci_hcd:usb6
 43:       4898       5996   PCI-MSI-edge      ahci
NMI:          0          0   Non-maskable interrupts
LOC:     116278      86951   Local timer interrupts
RES:      27385      27476   Rescheduling interrupts
CAL:         91         32   Function call interrupts
TLB:         32         96   TLB shootdowns
TRM:          0          0   Thermal event interrupts
THR:          0          0   Threshold APIC interrupts
SPU:          0          0   Spurious interrupts
ERR:          0
MIS:          0


> 
> > > This is possibly also related to the massive slowdown I get X uses 20%+
> > > CPU constantly and continually probes DDC, when I switch to battery,
> > > this I had expected to be fixed by the recent patch removing ACPI event
> > > handling, but strangely it still occurs.
> > 
> > You're the only person I've heard of with this problem.  You'll need to
> > figure out what's causing it.  We still handle ACPI events, it was just
> > an internal timer potentially firing off DDC that was removed.
> > 
> I wonder if it's the VBIOS triggering continuous events?  It may have
> started happening when I updated to revision A13 (the latest) of the
> Dell D830 BIOS.  Perhaps I'm the only tester with a D830?
> 
> Any idea how I could track this down?
>