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Date: Wed, 16 Nov 2011 11:14:41 +0100
Message-ID: <CAOZOX0WDQQeg4o5J9iQ_TpQgyYpTk5D3B4rpdTVR_4nGFVQ0wg@mail.gmail.com> (sfid-20111116_111446_135101_EEED2BB7)
Subject: Re: [PATCH] rt2800pci: handle spurious interrupts
From: Ivo Van Doorn <ivdoorn@gmail.com>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: "John W. Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org,
	Gertjan van Wingerde <gwingerde@gmail.com>,
	Helmut Schaa <helmut.schaa@googlemail.com>,
	Amir Hedayaty <hedayaty@gmail.com>
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Sender: linux-wireless-owner@vger.kernel.org
List-ID: <linux-wireless.vger.kernel.org>

Hi,

On Wed, Nov 16, 2011 at 11:09 AM, Stanislaw Gruszka <sgruszka@redhat.com> wrote:
> Some devices may generate spurious interrupts, we have to handle them
> otherwise interrupt line will be disabled with below message and driver
> will not work:
>
> [ 2052.114334] irq 17: nobody cared (try booting with the "irqpoll" option)
> [ 2052.114339] Pid: 0, comm: swapper Tainted: P ? ? ? ? ? 2.6.35.6-48.fc14.x86_64 #1
> [ 2052.114341] Call Trace:
> [ 2052.114342] ?<IRQ> ?[<ffffffff810a6e2b>] __report_bad_irq.clone.1+0x3d/0x8b
> [ 2052.114349] ?[<ffffffff810a6f93>] note_interrupt+0x11a/0x17f
> [ 2052.114352] ?[<ffffffff810a7a73>] handle_fasteoi_irq+0xa8/0xce
> [ 2052.114355] ?[<ffffffff8100c2ea>] handle_irq+0x88/0x90
> [ 2052.114357] ?[<ffffffff8146f034>] do_IRQ+0x5c/0xb4
> [ 2052.114360] ?[<ffffffff81469593>] ret_from_intr+0x0/0x11
> [ 2052.114361] ?<EOI> ?[<ffffffff8102b7f9>] ? native_safe_halt+0xb/0xd
> [ 2052.114366] ?[<ffffffff81010f03>] ? need_resched+0x23/0x2d
> [ 2052.114367] ?[<ffffffff8101102a>] default_idle+0x34/0x4f
> [ 2052.114370] ?[<ffffffff81008325>] cpu_idle+0xaa/0xcc
> [ 2052.114373] ?[<ffffffff81461f2a>] start_secondary+0x24d/0x28e
> [ 2052.114374] handlers:
> [ 2052.114375] [<ffffffff81332944>] (usb_hcd_irq+0x0/0x7c)
> [ 2052.114378] [<ffffffffa00697da>] (rt2800pci_interrupt+0x0/0x18d [rt2800pci])
> [ 2052.114384] Disabling IRQ #17
>
> Resolve:
> https://bugzilla.redhat.com/show_bug.cgi?id=658451
>
> Reported-and-tested-by: Amir Hedayaty <hedayaty@gmail.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>

Acked-by: Ivo van Doorn <IvDoorn@gmail.com>

> ---
> I changed rt2800pci only because get bug report for that device, not
> sure if similar changes are not needed for other rt2x00 PCI devices.

The ticket mentiones that the end-result is a slow connection,
this is also a bug in older chipsets. So could you prepare a patch
for the other drivers as well?

> ?drivers/net/wireless/rt2x00/rt2800pci.c | ? ?7 ++++++-
> ?1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
> index da48c8a..4dc2d0f 100644
> --- a/drivers/net/wireless/rt2x00/rt2800pci.c
> +++ b/drivers/net/wireless/rt2x00/rt2800pci.c
> @@ -880,8 +880,13 @@ static irqreturn_t rt2800pci_interrupt(int irq, void *dev_instance)
> ? ? ? ?rt2x00pci_register_read(rt2x00dev, INT_SOURCE_CSR, &reg);
> ? ? ? ?rt2x00pci_register_write(rt2x00dev, INT_SOURCE_CSR, reg);
>
> + ? ? ? /*
> + ? ? ? ?* Some devices can generate interrupts with empty CSR register, we
> + ? ? ? ?* "handle" such irq's to prevent interrupt controller treat them as
> + ? ? ? ?* spurious interrupts and disable irq line.
> + ? ? ? ?*/
> ? ? ? ?if (!reg)
> - ? ? ? ? ? ? ? return IRQ_NONE;
> + ? ? ? ? ? ? ? return IRQ_HANDLED;
>
> ? ? ? ?if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
> ? ? ? ? ? ? ? ?return IRQ_HANDLED;
> --
> 1.7.1
>
>