Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Jonathan Nieder]

Sven Joachim wrote:

> The laptop is an Acer TravelMate 2490 with a Broadcom chip:
>
> ,----
> | 06:02.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)
> | 	Subsystem: AMBIT Microsystem Corp. TravelMate 2410
> | 	Flags: bus master, fast devsel, latency 64, IRQ 10
> | 	Memory at d0002000 (32-bit, non-prefetchable) [size=8K]
> | 	Kernel driver in use: b43-pci-bridge
> `----

Odd.  Does it use that driver with both working and non-working
kernels?

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Sven Joachim]

On 2012-03-04 22:53 +0100, Jonathan Nieder wrote:

> Sven Joachim wrote:
>
>> The laptop is an Acer TravelMate 2490 with a Broadcom chip:
>>
>> ,----
>> | 06:02.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)
>> | 	Subsystem: AMBIT Microsystem Corp. TravelMate 2410
>> | 	Flags: bus master, fast devsel, latency 64, IRQ 10
>> | 	Memory at d0002000 (32-bit, non-prefetchable) [size=8K]
>> | 	Kernel driver in use: b43-pci-bridge
>> `----
>
> Odd.  Does it use that driver with both working and non-working
> kernels?

Yes, although lsmod just tells me that "b43" is loaded.  And
"dmesg | grep b43" shows this:

,----
| [    0.628622] b43-pci-bridge 0000:06:02.0: enabling device (0000 -> 0002)
| [    0.628780] b43-pci-bridge 0000:06:02.0: PCI INT A -> Link[LNKG] -> GSI 10 (level, low) -> IRQ 10
| [    0.628795] b43-pci-bridge 0000:06:02.0: setting latency timer to 64
| [    5.648519] b43-phy0: Broadcom 4318 WLAN found (core revision 9)
| [   36.267694] b43-phy0: Loading firmware version 410.2160 (2007-05-26 15:32:10)
`----

The kernel configuration has these b43 related parameters:

CONFIG_B43=m
CONFIG_B43_SSB=y
CONFIG_B43_PCI_AUTOSELECT=y
CONFIG_B43_PCICORE_AUTOSELECT=y
# CONFIG_B43_PCMCIA is not set
# CONFIG_B43_SDIO is not set
CONFIG_B43_PIO=y
# CONFIG_B43_PHY_N is not set
CONFIG_B43_PHY_LP=y
# CONFIG_B43_PHY_HT is not set
CONFIG_B43_HWRNG=y
# CONFIG_B43_DEBUG is not set
# CONFIG_B43LEGACY is not set
CONFIG_SSB_B43_PCI_BRIDGE=y


Cheers,
       Sven

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Stefan Lippers-Hollmann]

Hi

On Monday 05 March 2012, Sven Joachim wrote:
> On 2012-02-28 02:05 +0100, Greg KH wrote:
> 
> > 3.2-stable review patch.  If anyone has any objections, please let me know.
> 
> Alas, the commit below broke the WiFi on my laptop, where
> "iwlist wlan0 scan" now just reports: " wlan0     No scan results".
> 
> This is not specific to 3.2, the same problem exists in 3.0.23 and
> 3.3-rc6 while previous releases worked.

I can confirm this regression on an old PIII based notebook with a 
32 bit BCM4306/3 PCMCIA card:

02:00.0 Network controller [0280]: Broadcom Corporation BCM4306 802.11b/g Wireless LAN Controller [14e4:4320] (rev 03)
        Subsystem: Linksys WPC54G v1 / WPC54GS v1 802.11g Wireless-G Notebook Adapter [1737:4320]
        Flags: bus master, fast devsel, latency 64, IRQ 10
        Memory at 20000000 (32-bit, non-prefetchable) [size=8K]
        Capabilities: [40] Power Management version 2
        Kernel driver in use: b43-pci-bridge

I can observe these differences in the dmesg output (3.2.9 + current 
stable queue-3.2):

The kernel configuration is identical in both cases, the only 
difference is "genirq: Unmask oneshot irqs when thread was not woken"
being applied or not.

--- working	<-- 3.2.9 + current stable queue-3.2, with "genirq: Unmask oneshot irqs when thread was not woken" reverted
+++ broken	<-- 3.2.9 + current stable queue-3.2
@@ -125,6 +125,7 @@ Initializing cgroup subsys freezer
 Initializing cgroup subsys net_cls
 Initializing cgroup subsys blkio
 Initializing cgroup subsys perf_event
+CPU serial number disabled.
 mce: CPU supports 5 MCE banks
 SMP alternatives: switching to UP code
 Freeing SMP alternatives: 8k freed
@@ -137,9 +138,16 @@ SMP disabled
 Performance Events: 
 no APIC, boot with the "lapic" boot parameter to force-enable it.
 no hardware sampling interrupt available.
-Broken PMU hardware detected, using software events only.
+p6 PMU driver.
+... version:                0
+... bit width:              32
+... generic registers:      2
+... value mask:             00000000ffffffff
+... max period:             000000007fffffff
+... fixed-purpose events:   0
+... event mask:             0000000000000003
 Brought up 1 CPUs
 Total of 1 processors activated (1989.75 BogoMIPS).
 devtmpfs: initialized
 PM: Registering ACPI NVS region at eeff000 (4096 bytes)
 print_constraints: dummy: 
@@ -174,12 +182,12 @@ pci 0000:00:00.0: reg 10: [mem 0xec00000
 type 1 class 0x000604
 pci 0000:00:01.0: supports D1
 type 2 class 0x000607
-pci 0000:00:04.0: reg 10: [mem 0x10000000-0x10000fff]
+pci 0000:00:04.0: reg 10: [mem 0x00000000-0x00000fff]
 pci 0000:00:04.0: supports D1 D2
 pci 0000:00:04.0: PME# supported from D0 D1 D2 D3hot D3cold
 pci 0000:00:04.0: PME# disabled
 type 2 class 0x000607
-pci 0000:00:04.1: reg 10: [mem 0x14000000-0x14000fff]
+pci 0000:00:04.1: reg 10: [mem 0x00000000-0x00000fff]
 pci 0000:00:04.1: supports D1 D2
 pci 0000:00:04.1: PME# supported from D0 D1 D2 D3hot D3cold
 pci 0000:00:04.1: PME# disabled
@@ -299,6 +307,10 @@ pnp: PnP ACPI: found 11 devices
 ACPI: ACPI bus type pnp unregistered
 Switching to clocksource acpi_pm
 PCI: max bus depth: 1 pci_try_num: 2
+pci 0000:00:04.0: BAR 0: assigned [mem 0x10000000-0x10000fff]
+(PCI address [0x10000000-0x10000fff])
+pci 0000:00:04.1: BAR 0: assigned [mem 0x14000000-0x14000fff]
+(PCI address [0x14000000-0x14000fff])
 pci 0000:00:11.0: BAR 6: assigned [mem 0x10020000-0x1003ffff pref]
 pci 0000:00:04.1: BAR 16: assigned [mem 0x18000000-0x1bffffff]
 pci 0000:00:04.1: BAR 15: assigned [mem 0x1c000000-0x1fffffff pref]
@@ -326,9 +338,11 @@ pci 0000:00:01.0: setting latency timer
 enabled at IRQ 10
 PCI: setting IRQ 10 as level-triggered
 -> GSI 10 (level, low) -> IRQ 10
+pci 0000:00:04.0: setting latency timer to 64
 enabled at IRQ 11
 PCI: setting IRQ 11 as level-triggered
 -> GSI 11 (level, low) -> IRQ 11
+pci 0000:00:04.1: setting latency timer to 64
 pci_bus 0000:00: resource 0 [io  0x0000-0xffff]
 pci_bus 0000:00: resource 1 [mem 0x00000000-0xffffffff]
 pci_bus 0000:01: resource 1 [mem 0xe8100000-0xe81fffff]
@@ -562,20 +576,6 @@ b43-phy0: Hardware crypto acceleration n
 b43-phy0: QoS not supported by firmware
 ADDRCONF(NETDEV_UP): wlan0: link is not ready
 NET: Registered protocol family 17
-wlan0: authenticate with [redacted MAC address] (try 1)
-wlan0: authenticated
-wlan0: associate with [redacted MAC address] (try 1)
-wlan0: RX AssocResp from [redacted MAC address] (capab=0x411 status=0 aid=1)
-wlan0: associated
-ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
-cfg80211: Calling CRDA for country: DE
-Intel AES-NI instructions are not detected.
-cfg80211: Regulatory domain changed to country: DE
-cfg80211:     (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
-cfg80211:     (2400000 KHz - 2483500 KHz @ 40000 KHz), (N/A, 2000 mBm)
-cfg80211:     (5150000 KHz - 5250000 KHz @ 40000 KHz), (N/A, 2000 mBm)
-cfg80211:     (5250000 KHz - 5350000 KHz @ 40000 KHz), (N/A, 2000 mBm)
-cfg80211:     (5470000 KHz - 5725000 KHz @ 40000 KHz), (N/A, 2698 mBm)
 lp0: using parport0 (interrupt-driven).
 lp0: console ready
 ppdev: user-space parallel port driver
@@ -589,4 +589,3 @@ mtrr: base(0xf2000000) is not aligned on
 agpgart-via 0000:00:00.0: AGP 2.0 bridge
 agpgart-via 0000:00:00.0: putting AGP V2 device into 0x mode
 pci 0000:01:00.0: putting AGP V2 device into 0x mode
-wlan0: no IPv6 routers present

While I don't get any revealing error messages, once "genirq: Unmask 
oneshot irqs when thread was not woken" is applied the wlan card 
stops working (no scan results, unable to auth).

I cannot reproduce this problem on a different amd64/ 64 bit system 
with a BCM4318 PCI card, which continues to work fine.

Regards
	Stefan Lippers-Hollmann

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Linus Torvalds]

Thomas, should we just plan on reverting that commit from mainline? It
clearly causes regressions.

                Linus

On Sun, Mar 4, 2012 at 4:43 PM, Stefan Lippers-Hollmann <s.L-H@gmx.de> wrote:
> Hi
>
> On Monday 05 March 2012, Sven Joachim wrote:
>> On 2012-02-28 02:05 +0100, Greg KH wrote:
>>
>> > 3.2-stable review patch.  If anyone has any objections, please let me know.
>>
>> Alas, the commit below broke the WiFi on my laptop, where
>> "iwlist wlan0 scan" now just reports: " wlan0     No scan results".
>>
>> This is not specific to 3.2, the same problem exists in 3.0.23 and
>> 3.3-rc6 while previous releases worked.
>
> I can confirm this regression on an old PIII based notebook with a
> 32 bit BCM4306/3 PCMCIA card:
>
> 02:00.0 Network controller [0280]: Broadcom Corporation BCM4306 802.11b/g Wireless LAN Controller [14e4:4320] (rev 03)
>        Subsystem: Linksys WPC54G v1 / WPC54GS v1 802.11g Wireless-G Notebook Adapter [1737:4320]
>        Flags: bus master, fast devsel, latency 64, IRQ 10
>        Memory at 20000000 (32-bit, non-prefetchable) [size=8K]
>        Capabilities: [40] Power Management version 2
>        Kernel driver in use: b43-pci-bridge
>
> I can observe these differences in the dmesg output (3.2.9 + current
> stable queue-3.2):
>
> The kernel configuration is identical in both cases, the only
> difference is "genirq: Unmask oneshot irqs when thread was not woken"
> being applied or not.
>
> --- working     <-- 3.2.9 + current stable queue-3.2, with "genirq: Unmask oneshot irqs when thread was not woken" reverted
> +++ broken      <-- 3.2.9 + current stable queue-3.2
> @@ -125,6 +125,7 @@ Initializing cgroup subsys freezer
>  Initializing cgroup subsys net_cls
>  Initializing cgroup subsys blkio
>  Initializing cgroup subsys perf_event
> +CPU serial number disabled.
>  mce: CPU supports 5 MCE banks
>  SMP alternatives: switching to UP code
>  Freeing SMP alternatives: 8k freed
> @@ -137,9 +138,16 @@ SMP disabled
>  Performance Events:
>  no APIC, boot with the "lapic" boot parameter to force-enable it.
>  no hardware sampling interrupt available.
> -Broken PMU hardware detected, using software events only.
> +p6 PMU driver.
> +... version:                0
> +... bit width:              32
> +... generic registers:      2
> +... value mask:             00000000ffffffff
> +... max period:             000000007fffffff
> +... fixed-purpose events:   0
> +... event mask:             0000000000000003
>  Brought up 1 CPUs
>  Total of 1 processors activated (1989.75 BogoMIPS).
>  devtmpfs: initialized
>  PM: Registering ACPI NVS region at eeff000 (4096 bytes)
>  print_constraints: dummy:
> @@ -174,12 +182,12 @@ pci 0000:00:00.0: reg 10: [mem 0xec00000
>  type 1 class 0x000604
>  pci 0000:00:01.0: supports D1
>  type 2 class 0x000607
> -pci 0000:00:04.0: reg 10: [mem 0x10000000-0x10000fff]
> +pci 0000:00:04.0: reg 10: [mem 0x00000000-0x00000fff]
>  pci 0000:00:04.0: supports D1 D2
>  pci 0000:00:04.0: PME# supported from D0 D1 D2 D3hot D3cold
>  pci 0000:00:04.0: PME# disabled
>  type 2 class 0x000607
> -pci 0000:00:04.1: reg 10: [mem 0x14000000-0x14000fff]
> +pci 0000:00:04.1: reg 10: [mem 0x00000000-0x00000fff]
>  pci 0000:00:04.1: supports D1 D2
>  pci 0000:00:04.1: PME# supported from D0 D1 D2 D3hot D3cold
>  pci 0000:00:04.1: PME# disabled
> @@ -299,6 +307,10 @@ pnp: PnP ACPI: found 11 devices
>  ACPI: ACPI bus type pnp unregistered
>  Switching to clocksource acpi_pm
>  PCI: max bus depth: 1 pci_try_num: 2
> +pci 0000:00:04.0: BAR 0: assigned [mem 0x10000000-0x10000fff]
> +(PCI address [0x10000000-0x10000fff])
> +pci 0000:00:04.1: BAR 0: assigned [mem 0x14000000-0x14000fff]
> +(PCI address [0x14000000-0x14000fff])
>  pci 0000:00:11.0: BAR 6: assigned [mem 0x10020000-0x1003ffff pref]
>  pci 0000:00:04.1: BAR 16: assigned [mem 0x18000000-0x1bffffff]
>  pci 0000:00:04.1: BAR 15: assigned [mem 0x1c000000-0x1fffffff pref]
> @@ -326,9 +338,11 @@ pci 0000:00:01.0: setting latency timer
>  enabled at IRQ 10
>  PCI: setting IRQ 10 as level-triggered
>  -> GSI 10 (level, low) -> IRQ 10
> +pci 0000:00:04.0: setting latency timer to 64
>  enabled at IRQ 11
>  PCI: setting IRQ 11 as level-triggered
>  -> GSI 11 (level, low) -> IRQ 11
> +pci 0000:00:04.1: setting latency timer to 64
>  pci_bus 0000:00: resource 0 [io  0x0000-0xffff]
>  pci_bus 0000:00: resource 1 [mem 0x00000000-0xffffffff]
>  pci_bus 0000:01: resource 1 [mem 0xe8100000-0xe81fffff]
> @@ -562,20 +576,6 @@ b43-phy0: Hardware crypto acceleration n
>  b43-phy0: QoS not supported by firmware
>  ADDRCONF(NETDEV_UP): wlan0: link is not ready
>  NET: Registered protocol family 17
> -wlan0: authenticate with [redacted MAC address] (try 1)
> -wlan0: authenticated
> -wlan0: associate with [redacted MAC address] (try 1)
> -wlan0: RX AssocResp from [redacted MAC address] (capab=0x411 status=0 aid=1)
> -wlan0: associated
> -ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
> -cfg80211: Calling CRDA for country: DE
> -Intel AES-NI instructions are not detected.
> -cfg80211: Regulatory domain changed to country: DE
> -cfg80211:     (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
> -cfg80211:     (2400000 KHz - 2483500 KHz @ 40000 KHz), (N/A, 2000 mBm)
> -cfg80211:     (5150000 KHz - 5250000 KHz @ 40000 KHz), (N/A, 2000 mBm)
> -cfg80211:     (5250000 KHz - 5350000 KHz @ 40000 KHz), (N/A, 2000 mBm)
> -cfg80211:     (5470000 KHz - 5725000 KHz @ 40000 KHz), (N/A, 2698 mBm)
>  lp0: using parport0 (interrupt-driven).
>  lp0: console ready
>  ppdev: user-space parallel port driver
> @@ -589,4 +589,3 @@ mtrr: base(0xf2000000) is not aligned on
>  agpgart-via 0000:00:00.0: AGP 2.0 bridge
>  agpgart-via 0000:00:00.0: putting AGP V2 device into 0x mode
>  pci 0000:01:00.0: putting AGP V2 device into 0x mode
> -wlan0: no IPv6 routers present
>
> While I don't get any revealing error messages, once "genirq: Unmask
> oneshot irqs when thread was not woken" is applied the wlan card
> stops working (no scan results, unable to auth).
>
> I cannot reproduce this problem on a different amd64/ 64 bit system
> with a BCM4318 PCI card, which continues to work fine.
>
> Regards
>        Stefan Lippers-Hollmann

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

On Mon, 5 Mar 2012, Linus Torvalds wrote:

> Thomas, should we just plan on reverting that commit from mainline? It
> clearly causes regressions.

Give me a day or two to figure out why it breaks stuff. I have no idea
why it should wreckage anything.

Thanks,

	tglx

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

On Tue, 6 Mar 2012, Thomas Gleixner wrote:

> On Mon, 5 Mar 2012, Linus Torvalds wrote:
> 
> > Thomas, should we just plan on reverting that commit from mainline? It
> > clearly causes regressions.
> 
> Give me a day or two to figure out why it breaks stuff. I have no idea
> why it should wreckage anything.

Hmm. This is interesting. The b43 driver has a primary handler which
can return IRQ_NONE. So up to that change the interrupt line was kept
disabled when that happened. Possibly the driver relies on that
behaviour. Digging for a machine with a b43.

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

On Tue, 6 Mar 2012, Thomas Gleixner wrote:
> On Tue, 6 Mar 2012, Thomas Gleixner wrote:
> 
> > On Mon, 5 Mar 2012, Linus Torvalds wrote:
> > 
> > > Thomas, should we just plan on reverting that commit from mainline? It
> > > clearly causes regressions.
> > 
> > Give me a day or two to figure out why it breaks stuff. I have no idea
> > why it should wreckage anything.
> 
> Hmm. This is interesting. The b43 driver has a primary handler which
> can return IRQ_NONE. So up to that change the interrupt line was kept
> disabled when that happened. Possibly the driver relies on that
> behaviour. Digging for a machine with a b43.

Does not reproduce. Now I was looking at the driver again, it does not
use IRQ_ONESHOT anyway.

So for handle_fasteoi_irq() this patch is actually a NOOP. So the only
affected handler would be handle_level_irq(). Still can't see how it
changes the !IRQ_ONESHOT behaviour :(

Stephan, Sven: Can you please provide the output of /proc/interrupts ?

Thanks,

	tglx

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

On Mon, 5 Mar 2012, Stefan Lippers-Hollmann wrote:
> On Monday 05 March 2012, Sven Joachim wrote:
> > On 2012-02-28 02:05 +0100, Greg KH wrote:
> > 
> > > 3.2-stable review patch.  If anyone has any objections, please let me know.
> > 
> > Alas, the commit below broke the WiFi on my laptop, where
> > "iwlist wlan0 scan" now just reports: " wlan0     No scan results".
> > 
> > This is not specific to 3.2, the same problem exists in 3.0.23 and
> > 3.3-rc6 while previous releases worked.
> 
> I can confirm this regression on an old PIII based notebook with a 
> 32 bit BCM4306/3 PCMCIA card:
> 
> 02:00.0 Network controller [0280]: Broadcom Corporation BCM4306 802.11b/g Wireless LAN Controller [14e4:4320] (rev 03)
>         Subsystem: Linksys WPC54G v1 / WPC54GS v1 802.11g Wireless-G Notebook Adapter [1737:4320]
>         Flags: bus master, fast devsel, latency 64, IRQ 10
>         Memory at 20000000 (32-bit, non-prefetchable) [size=8K]
>         Capabilities: [40] Power Management version 2
>         Kernel driver in use: b43-pci-bridge
> 
> I can observe these differences in the dmesg output (3.2.9 + current 
> stable queue-3.2):
> 
> The kernel configuration is identical in both cases, the only 
> difference is "genirq: Unmask oneshot irqs when thread was not woken"
> being applied or not.
> 
> --- working	<-- 3.2.9 + current stable queue-3.2, with "genirq: Unmask oneshot irqs when thread was not woken" reverted
> +++ broken	<-- 3.2.9 + current stable queue-3.2
> @@ -125,6 +125,7 @@ Initializing cgroup subsys freezer
>  Initializing cgroup subsys net_cls
>  Initializing cgroup subsys blkio
>  Initializing cgroup subsys perf_event
> +CPU serial number disabled.

I can't see why reverting that genirq patch would cause this.

>  mce: CPU supports 5 MCE banks
>  SMP alternatives: switching to UP code
>  Freeing SMP alternatives: 8k freed
> @@ -137,9 +138,16 @@ SMP disabled
>  Performance Events: 
>  no APIC, boot with the "lapic" boot parameter to force-enable it.
>  no hardware sampling interrupt available.
> -Broken PMU hardware detected, using software events only.
> +p6 PMU driver.
> +... version:                0
> +... bit width:              32
> +... generic registers:      2
> +... value mask:             00000000ffffffff
> +... max period:             000000007fffffff
> +... fixed-purpose events:   0
> +... event mask:             0000000000000003

Ditto.

>  Brought up 1 CPUs
>  Total of 1 processors activated (1989.75 BogoMIPS).
>  devtmpfs: initialized
>  PM: Registering ACPI NVS region at eeff000 (4096 bytes)
>  print_constraints: dummy: 
> @@ -174,12 +182,12 @@ pci 0000:00:00.0: reg 10: [mem 0xec00000
>  type 1 class 0x000604
>  pci 0000:00:01.0: supports D1
>  type 2 class 0x000607
> -pci 0000:00:04.0: reg 10: [mem 0x10000000-0x10000fff]
> +pci 0000:00:04.0: reg 10: [mem 0x00000000-0x00000fff]

Even more. 

There is something extremly fishy.

Thanks,

	tglx

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Sven Joachim]

Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:

> Stephan, Sven: Can you please provide the output of /proc/interrupts ?

Here is mine, from a freshly booted 3.3-rc6 kernel.

Cheers,
       Sven

           CPU0       
  0:      25050    XT-PIC-XT-PIC    timer
  1:        101    XT-PIC-XT-PIC    i8042
  2:          0    XT-PIC-XT-PIC    cascade
  3:          1    XT-PIC-XT-PIC  
  4:          1    XT-PIC-XT-PIC  
  5:          0    XT-PIC-XT-PIC    ehci_hcd:usb1, uhci_hcd:usb2
  6:          1    XT-PIC-XT-PIC    i915, uhci_hcd:usb5, yenta
  7:          1    XT-PIC-XT-PIC  
  8:          0    XT-PIC-XT-PIC    rtc0
  9:        634    XT-PIC-XT-PIC    acpi
 10:        341    XT-PIC-XT-PIC    uhci_hcd:usb4, snd_hda_intel, b43
 11:          0    XT-PIC-XT-PIC    uhci_hcd:usb3
 12:        144    XT-PIC-XT-PIC    i8042
 14:       4141    XT-PIC-XT-PIC    ata_piix
 15:          0    XT-PIC-XT-PIC    ata_piix
NMI:          0   Non-maskable interrupts
MCE:          0   Machine check exceptions
MCP:          1   Machine check polls
ERR:          0

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Sven Joachim]

Am 06.03.2012 um 20:45 schrieb Thomas Gleixner:

> On Mon, 5 Mar 2012, Stefan Lippers-Hollmann wrote:
>> On Monday 05 March 2012, Sven Joachim wrote:
>> > On 2012-02-28 02:05 +0100, Greg KH wrote:
>> > 
>> > > 3.2-stable review patch.  If anyone has any objections, please let me know.
>> > 
>> > Alas, the commit below broke the WiFi on my laptop, where
>> > "iwlist wlan0 scan" now just reports: " wlan0     No scan results".
>> > 
>> > This is not specific to 3.2, the same problem exists in 3.0.23 and
>> > 3.3-rc6 while previous releases worked.
>> 
>> I can confirm this regression on an old PIII based notebook with a 
>> 32 bit BCM4306/3 PCMCIA card:
>> 
>> 02:00.0 Network controller [0280]: Broadcom Corporation BCM4306 802.11b/g Wireless LAN Controller [14e4:4320] (rev 03)
>>         Subsystem: Linksys WPC54G v1 / WPC54GS v1 802.11g Wireless-G Notebook Adapter [1737:4320]
>>         Flags: bus master, fast devsel, latency 64, IRQ 10
>>         Memory at 20000000 (32-bit, non-prefetchable) [size=8K]
>>         Capabilities: [40] Power Management version 2
>>         Kernel driver in use: b43-pci-bridge
>> 
>> I can observe these differences in the dmesg output (3.2.9 + current 
>> stable queue-3.2):
>> 
>> The kernel configuration is identical in both cases, the only 
>> difference is "genirq: Unmask oneshot irqs when thread was not woken"
>> being applied or not.
>> 
>> --- working	<-- 3.2.9 + current stable queue-3.2, with "genirq: Unmask oneshot irqs when thread was not woken" reverted
>> +++ broken	<-- 3.2.9 + current stable queue-3.2
>> @@ -125,6 +125,7 @@ Initializing cgroup subsys freezer
>>  Initializing cgroup subsys net_cls
>>  Initializing cgroup subsys blkio
>>  Initializing cgroup subsys perf_event
>> +CPU serial number disabled.
>
> I can't see why reverting that genirq patch would cause this.
>
>>  mce: CPU supports 5 MCE banks
>>  SMP alternatives: switching to UP code
>>  Freeing SMP alternatives: 8k freed
>> @@ -137,9 +138,16 @@ SMP disabled
>>  Performance Events: 
>>  no APIC, boot with the "lapic" boot parameter to force-enable it.
>>  no hardware sampling interrupt available.
>> -Broken PMU hardware detected, using software events only.
>> +p6 PMU driver.
>> +... version:                0
>> +... bit width:              32
>> +... generic registers:      2
>> +... value mask:             00000000ffffffff
>> +... max period:             000000007fffffff
>> +... fixed-purpose events:   0
>> +... event mask:             0000000000000003
>
> Ditto.
>
>>  Brought up 1 CPUs
>>  Total of 1 processors activated (1989.75 BogoMIPS).
>>  devtmpfs: initialized
>>  PM: Registering ACPI NVS region at eeff000 (4096 bytes)
>>  print_constraints: dummy: 
>> @@ -174,12 +182,12 @@ pci 0000:00:00.0: reg 10: [mem 0xec00000
>>  type 1 class 0x000604
>>  pci 0000:00:01.0: supports D1
>>  type 2 class 0x000607
>> -pci 0000:00:04.0: reg 10: [mem 0x10000000-0x10000fff]
>> +pci 0000:00:04.0: reg 10: [mem 0x00000000-0x00000fff]
>
> Even more. 

FWIW, I don't see any such differences on my system (with 3.3-rc6).

> There is something extremly fishy.

Cheers,
       Sven

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Stefan Lippers-Hollmann]

[-- Attachment #1.1: Type: Text/Plain, Size: 1585 bytes --]

Hi

On Tuesday 06 March 2012, Thomas Gleixner wrote:
> On Tue, 6 Mar 2012, Thomas Gleixner wrote:
> > On Tue, 6 Mar 2012, Thomas Gleixner wrote:
> > 
> > > On Mon, 5 Mar 2012, Linus Torvalds wrote:
> > > 
> > > > Thomas, should we just plan on reverting that commit from mainline? It
> > > > clearly causes regressions.
> > > 
> > > Give me a day or two to figure out why it breaks stuff. I have no idea
> > > why it should wreckage anything.
> > 
> > Hmm. This is interesting. The b43 driver has a primary handler which
> > can return IRQ_NONE. So up to that change the interrupt line was kept
> > disabled when that happened. Possibly the driver relies on that
> > behaviour. Digging for a machine with a b43.
> 
> Does not reproduce. Now I was looking at the driver again, it does not
> use IRQ_ONESHOT anyway.
> 
> So for handle_fasteoi_irq() this patch is actually a NOOP. So the only
> affected handler would be handle_level_irq(). Still can't see how it
> changes the !IRQ_ONESHOT behaviour :(
> 
> Stephan, Sven: Can you please provide the output of /proc/interrupts ?

Full /proc/interrupts and gzipped dmesg attached for kernel 3.2.9 + 
current stable queue-3.2, no difference in the interrupt output between
working and broken state. Both outputs taken immediately after a cold
reboot.

*.broken is with "genirq: Unmask oneshot irqs when thread was not 
woken" applied, resulting in empty wlan scan results, no auth).

*.working with only this patch reverted (3 wlan cells visible, 
immediate auth.

Regards
	Stefan Lippers-Hollmann

[-- Attachment #1.2: dmesg.broken.gz --]
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[-- Attachment #1.4: interrupts.broken --]
[-- Type: text/plain, Size: 1249 bytes --]

           CPU0       
  0:      16875    XT-PIC-XT-PIC    timer
  1:         94    XT-PIC-XT-PIC    i8042
  2:          0    XT-PIC-XT-PIC    cascade
  3:          2    XT-PIC-XT-PIC  
  4:          2    XT-PIC-XT-PIC  
  5:          3    XT-PIC-XT-PIC    firewire_ohci, snd_via82xx
  6:          2    XT-PIC-XT-PIC    floppy
  7:          1    XT-PIC-XT-PIC    parport0
  8:          0    XT-PIC-XT-PIC    rtc0
  9:          0    XT-PIC-XT-PIC    acpi
 10:          3    XT-PIC-XT-PIC    yenta, b43
 11:          2    XT-PIC-XT-PIC    uhci_hcd:usb1, yenta
 12:        107    XT-PIC-XT-PIC    i8042
 14:       6431    XT-PIC-XT-PIC    pata_via
 15:         80    XT-PIC-XT-PIC    pata_via
NMI:          0   Non-maskable interrupts
LOC:          0   Local timer interrupts
SPU:          0   Spurious interrupts
PMI:          0   Performance monitoring interrupts
IWI:          0   IRQ work interrupts
RES:          0   Rescheduling interrupts
CAL:          0   Function call interrupts
TLB:          0   TLB shootdowns
TRM:          0   Thermal event interrupts
THR:          0   Threshold APIC interrupts
MCE:          0   Machine check exceptions
MCP:          1   Machine check polls
ERR:          0
MIS:          0

[-- Attachment #1.5: interrupts.working --]
[-- Type: text/plain, Size: 1249 bytes --]

           CPU0       
  0:      17967    XT-PIC-XT-PIC    timer
  1:        196    XT-PIC-XT-PIC    i8042
  2:          0    XT-PIC-XT-PIC    cascade
  3:          2    XT-PIC-XT-PIC  
  4:          2    XT-PIC-XT-PIC  
  5:          3    XT-PIC-XT-PIC    firewire_ohci, snd_via82xx
  6:          2    XT-PIC-XT-PIC    floppy
  7:          1    XT-PIC-XT-PIC    parport0
  8:          0    XT-PIC-XT-PIC    rtc0
  9:          0    XT-PIC-XT-PIC    acpi
 10:        527    XT-PIC-XT-PIC    yenta, b43
 11:          2    XT-PIC-XT-PIC    uhci_hcd:usb1, yenta
 12:        107    XT-PIC-XT-PIC    i8042
 14:       6491    XT-PIC-XT-PIC    pata_via
 15:         80    XT-PIC-XT-PIC    pata_via
NMI:          0   Non-maskable interrupts
LOC:          0   Local timer interrupts
SPU:          0   Spurious interrupts
PMI:          0   Performance monitoring interrupts
IWI:          0   IRQ work interrupts
RES:          0   Rescheduling interrupts
CAL:          0   Function call interrupts
TLB:          0   TLB shootdowns
TRM:          0   Thermal event interrupts
THR:          0   Threshold APIC interrupts
MCE:          0   Machine check exceptions
MCP:          1   Machine check polls
ERR:          0
MIS:          0

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Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

On Tue, 6 Mar 2012, Sven Joachim wrote:
> Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:
> 
> > Stephan, Sven: Can you please provide the output of /proc/interrupts ?
> 
> Here is mine, from a freshly booted 3.3-rc6 kernel.
> 
> Cheers,
>        Sven
> 
>            CPU0       
>   0:      25050    XT-PIC-XT-PIC    timer
>   1:        101    XT-PIC-XT-PIC    i8042
>   2:          0    XT-PIC-XT-PIC    cascade
>   3:          1    XT-PIC-XT-PIC  
>   4:          1    XT-PIC-XT-PIC  
>   5:          0    XT-PIC-XT-PIC    ehci_hcd:usb1, uhci_hcd:usb2
>   6:          1    XT-PIC-XT-PIC    i915, uhci_hcd:usb5, yenta
>   7:          1    XT-PIC-XT-PIC  
>   8:          0    XT-PIC-XT-PIC    rtc0
>   9:        634    XT-PIC-XT-PIC    acpi
>  10:        341    XT-PIC-XT-PIC    uhci_hcd:usb4, snd_hda_intel, b43

Ah, XT-PIC uses handle_level_irq(). /me bangs head against desk.

Does the patch below fix the problem for you ?

Thanks,

	tglx

----------------->
Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set

commit ac5637611(genirq: Unmask oneshot irqs when thread was not
woken) fails to unmask when a !IRQ_ONESHOT threaded handler is handled
by handle_level_irq. This happens because thread_mask is or'ed
unconditionally in irq_wake_thread(), but for !IRQ_ONESHOT interrupts
never cleared. So the check for !desc->thread_active fails and keeps
the interrupt disabled.

Keep the thread_mask zero for !IRQ_ONESHOT interrupts.

Reported-by: Sven Joachim <svenjoac@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

Index: linux-2.6/kernel/irq/manage.c
===================================================================
--- linux-2.6.orig/kernel/irq/manage.c
+++ linux-2.6/kernel/irq/manage.c
@@ -996,11 +996,13 @@ __setup_irq(unsigned int irq, struct irq
 	 * Setup the thread mask for this irqaction. Unlikely to have
 	 * 32 resp 64 irqs sharing one line, but who knows.
 	 */
-	if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
-		ret = -EBUSY;
-		goto out_mask;
+	if (new->flags & IRQF_ONESHOT) {
+		if (thread_mask == ~0UL) {
+			ret = -EBUSY;
+			goto out_mask;
+		}
+		new->thread_mask = new->flags & IRQF_ONESHOT;
 	}
-	new->thread_mask = 1 << ffz(thread_mask);
 
 	if (!shared) {
 		init_waitqueue_head(&desc->wait_for_threads);

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

On Tue, 6 Mar 2012, Thomas Gleixner wrote:
> On Tue, 6 Mar 2012, Sven Joachim wrote:
> > Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:
> > 
> > > Stephan, Sven: Can you please provide the output of /proc/interrupts ?
> > 
> > Here is mine, from a freshly booted 3.3-rc6 kernel.
> > 
> > Cheers,
> >        Sven
> > 
> >            CPU0       
> >   0:      25050    XT-PIC-XT-PIC    timer
> >   1:        101    XT-PIC-XT-PIC    i8042
> >   2:          0    XT-PIC-XT-PIC    cascade
> >   3:          1    XT-PIC-XT-PIC  
> >   4:          1    XT-PIC-XT-PIC  
> >   5:          0    XT-PIC-XT-PIC    ehci_hcd:usb1, uhci_hcd:usb2
> >   6:          1    XT-PIC-XT-PIC    i915, uhci_hcd:usb5, yenta
> >   7:          1    XT-PIC-XT-PIC  
> >   8:          0    XT-PIC-XT-PIC    rtc0
> >   9:        634    XT-PIC-XT-PIC    acpi
> >  10:        341    XT-PIC-XT-PIC    uhci_hcd:usb4, snd_hda_intel, b43
> 
> Ah, XT-PIC uses handle_level_irq(). /me bangs head against desk.

Ha, nosmp on the command line lets me reproduce as well and the patch
fixes it. Duh, stupid me.
 
Thanks,
 
 	tglx

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Sven Joachim]

Am 06.03.2012 um 21:26 schrieb Thomas Gleixner:

> On Tue, 6 Mar 2012, Sven Joachim wrote:
>> Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:
>> 
>> > Stephan, Sven: Can you please provide the output of /proc/interrupts ?
>> 
>> Here is mine, from a freshly booted 3.3-rc6 kernel.
>> 
>> Cheers,
>>        Sven
>> 
>>            CPU0       
>>   0:      25050    XT-PIC-XT-PIC    timer
>>   1:        101    XT-PIC-XT-PIC    i8042
>>   2:          0    XT-PIC-XT-PIC    cascade
>>   3:          1    XT-PIC-XT-PIC  
>>   4:          1    XT-PIC-XT-PIC  
>>   5:          0    XT-PIC-XT-PIC    ehci_hcd:usb1, uhci_hcd:usb2
>>   6:          1    XT-PIC-XT-PIC    i915, uhci_hcd:usb5, yenta
>>   7:          1    XT-PIC-XT-PIC  
>>   8:          0    XT-PIC-XT-PIC    rtc0
>>   9:        634    XT-PIC-XT-PIC    acpi
>>  10:        341    XT-PIC-XT-PIC    uhci_hcd:usb4, snd_hda_intel, b43
>
> Ah, XT-PIC uses handle_level_irq(). /me bangs head against desk.
>
> Does the patch below fix the problem for you ?

Yep, it does.  Thanks!

> ----------------->
> Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set
>
> commit ac5637611(genirq: Unmask oneshot irqs when thread was not
> woken) fails to unmask when a !IRQ_ONESHOT threaded handler is handled
> by handle_level_irq. This happens because thread_mask is or'ed
> unconditionally in irq_wake_thread(), but for !IRQ_ONESHOT interrupts
> never cleared. So the check for !desc->thread_active fails and keeps
> the interrupt disabled.
>
> Keep the thread_mask zero for !IRQ_ONESHOT interrupts.
>
> Reported-by: Sven Joachim <svenjoac@gmx.de>
> Cc: stable@vger.kernel.org
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>
> Index: linux-2.6/kernel/irq/manage.c
> ===================================================================
> --- linux-2.6.orig/kernel/irq/manage.c
> +++ linux-2.6/kernel/irq/manage.c
> @@ -996,11 +996,13 @@ __setup_irq(unsigned int irq, struct irq
>  	 * Setup the thread mask for this irqaction. Unlikely to have
>  	 * 32 resp 64 irqs sharing one line, but who knows.
>  	 */
> -	if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
> -		ret = -EBUSY;
> -		goto out_mask;
> +	if (new->flags & IRQF_ONESHOT) {
> +		if (thread_mask == ~0UL) {
> +			ret = -EBUSY;
> +			goto out_mask;
> +		}
> +		new->thread_mask = new->flags & IRQF_ONESHOT;
>  	}
> -	new->thread_mask = 1 << ffz(thread_mask);
>  
>  	if (!shared) {
>  		init_waitqueue_head(&desc->wait_for_threads);

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Stefan Lippers-Hollmann]

[-- Attachment #1: Type: Text/Plain, Size: 1515 bytes --]

Hi

On Tuesday 06 March 2012, Thomas Gleixner wrote:
> On Tue, 6 Mar 2012, Sven Joachim wrote:
> > Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:
> > 
> > > Stephan, Sven: Can you please provide the output of /proc/interrupts ?
> > 
> > Here is mine, from a freshly booted 3.3-rc6 kernel.
> > 
> > Cheers,
> >        Sven
> > 
> >            CPU0       
> >   0:      25050    XT-PIC-XT-PIC    timer
[…]
> >  10:        341    XT-PIC-XT-PIC    uhci_hcd:usb4, snd_hda_intel, b43
> 
> Ah, XT-PIC uses handle_level_irq(). /me bangs head against desk.
> 
> Does the patch below fix the problem for you ?
> 
> Thanks,
> 
> 	tglx
> 
> ----------------->
> Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set
> 
> commit ac5637611(genirq: Unmask oneshot irqs when thread was not
> woken) fails to unmask when a !IRQ_ONESHOT threaded handler is handled
> by handle_level_irq. This happens because thread_mask is or'ed
> unconditionally in irq_wake_thread(), but for !IRQ_ONESHOT interrupts
> never cleared. So the check for !desc->thread_active fails and keeps
> the interrupt disabled.
> 
> Keep the thread_mask zero for !IRQ_ONESHOT interrupts.
[…]

I can confirm that this patch, applied to 2.6.9, including "genirq: 
Unmask oneshot irqs when thread was not woken", and + the current 
stable queue-3.2 fixes b43 wlan operations. Feel free to add 
Tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
if you like.

Thanks a lot
	Stefan Lippers-Hollmann


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Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

Linus,

On Tue, 6 Mar 2012, Sven Joachim wrote:
> Am 06.03.2012 um 21:26 schrieb Thomas Gleixner:
> 
> > On Tue, 6 Mar 2012, Sven Joachim wrote:
> >> Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:
> >> 
> >> > Stephan, Sven: Can you please provide the output of /proc/interrupts ?
> >> 
> >> Here is mine, from a freshly booted 3.3-rc6 kernel.
> >> 
> >> Cheers,
> >>        Sven
> >> 
> >>            CPU0       
> >>   0:      25050    XT-PIC-XT-PIC    timer
> >>   1:        101    XT-PIC-XT-PIC    i8042
> >>   2:          0    XT-PIC-XT-PIC    cascade
> >>   3:          1    XT-PIC-XT-PIC  
> >>   4:          1    XT-PIC-XT-PIC  
> >>   5:          0    XT-PIC-XT-PIC    ehci_hcd:usb1, uhci_hcd:usb2
> >>   6:          1    XT-PIC-XT-PIC    i915, uhci_hcd:usb5, yenta
> >>   7:          1    XT-PIC-XT-PIC  
> >>   8:          0    XT-PIC-XT-PIC    rtc0
> >>   9:        634    XT-PIC-XT-PIC    acpi
> >>  10:        341    XT-PIC-XT-PIC    uhci_hcd:usb4, snd_hda_intel, b43
> >
> > Ah, XT-PIC uses handle_level_irq(). /me bangs head against desk.
> >
> > Does the patch below fix the problem for you ?
> 
> Yep, it does.  Thanks!

Can you pick it up directly or want me to send it via tip ?

Thanks,

	tglx

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Linus Torvalds]

On Tue, Mar 6, 2012 at 12:26 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set

Umm. Apparently this patch fixes the bug, but the patch itself is just insane.

> -       if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
> -               ret = -EBUSY;
> -               goto out_mask;
> +       if (new->flags & IRQF_ONESHOT) {
> +               if (thread_mask == ~0UL) {
> +                       ret = -EBUSY;
> +                       goto out_mask;
> +               }
> +               new->thread_mask = new->flags & IRQF_ONESHOT;
>        }
> -       new->thread_mask = 1 << ffz(thread_mask);

WHAT?

You just checked that "new->flags & IRQF_ONESHOT" nonzero, and inside
that if-statement, you then do

  new->thread_mask = new->flags & IRQF_ONESHOT;

which is just crazy. Why don't you just do

    new->thread_mask = IRQF_ONESHOT;

if that is what you actually meant?

What is that code actually *supposed* to do?

Also, what was the meaning of that old insane line:

   new->thread_mask = 1 << ffz(thread_mask);

which you removed? It was crap, I agree, but what was the thinking
behind it? And the reason it was crap is because that's a crazy
expression that could be written better ways (*), and it needs a
comment on what the heck the point of it was..

So stop with these "random code" snippets, and explain what the f*&^
the code is meant to do, AND THEN WRITE THE CODE IN A SANE MANNER
instead of posting these kinds of insane patches.

Because right now it really looks like the "random monkey" approach to
programming.

                   Linus

(*) "1 << ffz(a)" can be written as

   a = ~a;        /* Turn the zero bits into 1 bits */
   a &= -a;      /* .. and find the first one. */

without ever doing any insane bit scanning.

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Linus Torvalds]

On Tue, Mar 6, 2012 at 1:11 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Can you pick it up directly or want me to send it via tip ?

I can certainly pick it up directly, but I want the sane version, not
the "random monkeys typing" version. Please.

                   Linus

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Linus Torvalds]

On Tue, Mar 6, 2012 at 1:40 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> (*) "1 << ffz(a)" can be written as
>
>   a = ~a;        /* Turn the zero bits into 1 bits */
>   a &= -a;      /* .. and find the first one. */
>
> without ever doing any insane bit scanning.

Alternatively, wite it directly as "(a+1) &~a", which is the same
expression just written differently (due to "-a == ~a+1")

Yeah, I've been playing too much with the bitwise optimizations of the
dentry cache name comparisons lately.

                   Linus

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Thomas Gleixner]

On Tue, 6 Mar 2012, Linus Torvalds wrote:
> On Tue, Mar 6, 2012 at 12:26 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> without ever doing any insane bit scanning.

Duh, yes. That's really insane. I first did

- new->thread_mask = 1 << ffz(thread_mask);
+ new->thread_mask = (new->flags & IRQF_ONESHOT) ? 1 << ffz(thread_mask) : 0;

and then decided to move it into the already existing new->flags &
IRQF_ONESHOT check section and deleted the wrong part ....

/me looks for a huge brown paperbag.

Thanks for catching it !

       tglx

-------------->
Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set

commit ac5637611(genirq: Unmask oneshot irqs when thread was not
woken) fails to unmask when a !IRQ_ONESHOT threaded handler is handled
by handle_level_irq. This happens because thread_mask is or'ed
unconditionally in irq_wake_thread(), but for !IRQ_ONESHOT interrupts
never cleared. So the check for !desc->thread_active fails and keeps
the interrupt disabled.

Keep the thread_mask zero for !IRQ_ONESHOT interrupts.

Document the thread_mask magic while at it.

Reported-by: Sven Joachim <svenjoac@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

Index: tip/kernel/irq/manage.c
===================================================================
--- tip.orig/kernel/irq/manage.c
+++ tip/kernel/irq/manage.c
@@ -985,6 +985,11 @@ __setup_irq(unsigned int irq, struct irq
 
 		/* add new interrupt at end of irq queue */
 		do {
+			/*
+			 * Or all existing action->thread_mask bits,
+			 * so we can find the next zero bit for this
+			 * new action.
+			 */
 			thread_mask |= old->thread_mask;
 			old_ptr = &old->next;
 			old = *old_ptr;
@@ -993,14 +998,41 @@ __setup_irq(unsigned int irq, struct irq
 	}
 
 	/*
-	 * Setup the thread mask for this irqaction. Unlikely to have
-	 * 32 resp 64 irqs sharing one line, but who knows.
+	 * Setup the thread mask for this irqaction for ONESHOT. For
+	 * !ONESHOT irqs the thread mask is 0 so we can avoid a
+	 * conditional in irq_wake_thread().
 	 */
-	if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
-		ret = -EBUSY;
-		goto out_mask;
+	if (new->flags & IRQF_ONESHOT) {
+		/*
+		 * Unlikely to have 32 resp 64 irqs sharing one line,
+		 * but who knows.
+		 */
+		if (thread_mask == ~0UL) {
+			ret = -EBUSY;
+			goto out_mask;
+		}
+		/*
+		 * The thread_mask for the action is or'ed to
+		 * desc->thread_active to indicate that the
+		 * IRQF_ONESHOT thread handler has been woken, but not
+		 * yet finished. The bit is cleared when a thread
+		 * completes. When all threads of a shared interrupt
+		 * line have completed desc->threads_active becomes
+		 * zero and the interrupt line is unmasked. See
+		 * handle.c:irq_wake_thread() for further information.
+		 *
+		 * If no thread is woken by primary (hard irq context)
+		 * interrupt handlers, then desc->threads_active is
+		 * also checked for zero to unmask the irq line in the
+		 * affected hard irq flow handlers
+		 * (handle_[fasteoi|level]_irq).
+		 *
+		 * The new action gets the first zero bit of
+		 * thread_mask assigned. See the loop above which or's
+		 * all existing action->thread_mask bits.
+		 */
+		new->thread_mask = 1 << ffz(thread_mask);
 	}
-	new->thread_mask = 1 << ffz(thread_mask);
 
 	if (!shared) {
 		init_waitqueue_head(&desc->wait_for_threads);

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Linus Torvalds]

On Tue, Mar 6, 2012 at 2:18 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set

Ok, can we get this fixed version tested too by people who saw the problem?

Just to make sure..

Thanks,

                     Linus

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Stefan Lippers-Hollmann]

Hi

On Wednesday 07 March 2012, Linus Torvalds wrote:
> On Tue, Mar 6, 2012 at 2:18 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set
> 
> Ok, can we get this fixed version tested too by people who saw the problem?
> 
> Just to make sure..
[…]

This variant is also working fine on PIII/ coppermine and bcm4306/3.

Tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>

Regards
	Stefan Lippers-Hollmann

Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

[Sven Joachim]

On 2012-03-06 23:33 +0100, Linus Torvalds wrote:

> On Tue, Mar 6, 2012 at 2:18 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
>> Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set
>
> Ok, can we get this fixed version tested too by people who saw the problem?

It works for me.

Cheers,
       Sven