linux-toradex.git/kernel/irq/resend.c, branch v2.6.27.5

genirq: suppress resend of level interrupts

2007-08-12T18:05:45+00:00

Level type interrupts are resent by the interrupt hardware when they are
still active at irq_enable().

Suppress the resend mechanism for interrupts marked as level.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Linus Torvalds

Revert "genirq: temporary fix for level-triggered IRQ resend"

2007-08-09T15:10:16+00:00

This reverts commit 0fc4969b866671dfe39b1a9119d0fdc7ea0f63e5.  It was
always meant to be temporary, but it's generating more useless noise
than anything else, and we probably should never have done it in the
generic kernel (only had the people involved test it on their own).

Signed-off-by: Linus Torvalds

genirq: temporary fix for level-triggered IRQ resend

2007-08-02T03:46:22+00:00

Marcin Slusarz reported a ne2k-pci "hung network interface" regression.

delayed disable relies on the ability to re-trigger the interrupt in the
case that a real interrupt happens after the software disable was set.
In this case we actually disable the interrupt on the hardware level
_after_ it occurred.

On enable_irq, we need to re-trigger the interrupt. On i386 this relies
on a hardware resend mechanism (send_IPI_self()).

Actually we only need the resend for edge type interrupts. Level type
interrupts come back once enable_irq() re-enables the interrupt line.

I assume that the interrupt in question is level triggered because it is
shared and above the legacy irqs 0-15:

	17:         12   IO-APIC-fasteoi   eth1, eth0

Looking into the IO_APIC code, the resend via send_IPI_self() happens
unconditionally. So the resend is done for level and edge interrupts.
This makes the problem more mysterious.

The code in question lib8390.c does

	disable_irq();
	fiddle_with_the_network_card_hardware()
	enable_irq();

The fiddle_with_the_network_card_hardware() might cause interrupts,
which are cleared in the same code path again,

Marcin found that when he disables the irq line on the hardware level
(removing the delayed disable) the card is kept alive.

So the difference is that we can get a resend on enable_irq, when an
interrupt happens during the time, where we are in the disabled region.

Signed-off-by: Ingo Molnar 
Signed-off-by: Linus Torvalds

[PATCH] ixp4xxdefconfig arm fixes

2006-10-06T19:11:08+00:00

With the following patch, the ixp4xxdefconfig builds correctly.  I'll
test some more configs if I get some time.

Signed-off-by: Frederik Deweerdt 
Signed-off-by: Linus Torvalds

[PATCH] genirq: fix typo in IRQ resend

2006-09-16T19:54:30+00:00

Fix a bug where the IRQ_PENDING flag is never cleared and the ISR is called
endlessly without an actual interrupt.

Signed-off-by: Imre Deak 
Acked-by: Thomas Gleixner 
Acked-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] genirq: core

2006-06-29T17:26:24+00:00

Core genirq support: add the irq-chip and irq-flow abstractions.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] genirq: add genirq sw IRQ-retrigger

2006-06-29T17:26:23+00:00

Enable platforms that do not have a hardware-assisted hardirq-resend mechanism
to resend them via a softirq-driven IRQ emulation mechanism.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds