| Message ID | 20160628031139.12500-1-sam@mendozajonas.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Tue, 2016-28-06 at 03:11:38 UTC, Sam Mendoza-Jonas wrote: > Commit 2def86a7200c > ("hvc: Convert to using interrupts instead of opal events") > enabled the use of interrupts in the hvc_driver for OPAL platforms. > However on machines with more than one hvc console, any console after > the first will fail to register an interrupt handler in > notifier_add_irq() since all consoles share the same IRQ number but do > not set the IRQF_SHARED flag: > > [ 51.179907] genirq: Flags mismatch irq 31. 00000000 (hvc_console) vs. > 00000000 (hvc_console) > [ 51.180010] hvc_open: request_irq failed with rc -16. > > This error propagates up to hvc_open() and the console is closed, but > OPAL will still generate interrupts that are not handled, leading to > rcu_sched stall warnings. > > Set IRQF_SHARED when calling request_irq, allowing additional consoles > to start properly. This is only set for consoles handled by > hvc_opal_probe(), leaving other types unaffected. > > Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Greg I'm assuming you'll take this unless you tell me otherwise. cheers
diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h index 9131019..798c48d 100644 --- a/drivers/tty/hvc/hvc_console.h +++ b/drivers/tty/hvc/hvc_console.h @@ -60,6 +60,7 @@ struct hvc_struct { struct winsize ws; struct work_struct tty_resize; struct list_head next; + unsigned long flags; }; /* implemented by a low level driver */ diff --git a/drivers/tty/hvc/hvc_irq.c b/drivers/tty/hvc/hvc_irq.c index c9adb05..57d9df7 100644 --- a/drivers/tty/hvc/hvc_irq.c +++ b/drivers/tty/hvc/hvc_irq.c @@ -14,6 +14,9 @@ static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance) /* if hvc_poll request a repoll, then kick the hvcd thread */ if (hvc_poll(dev_instance)) hvc_kick(); + /* We're safe to always return IRQ_HANDLED as the hvcd thread will + * iterate through each hvc_struct + */ return IRQ_HANDLED; } @@ -28,8 +31,8 @@ int notifier_add_irq(struct hvc_struct *hp, int irq) hp->irq_requested = 0; return 0; } - rc = request_irq(irq, hvc_handle_interrupt, 0, - "hvc_console", hp); + rc = request_irq(irq, hvc_handle_interrupt, hp->flags, + "hvc_console", hp); if (!rc) hp->irq_requested = 1; return rc; diff --git a/drivers/tty/hvc/hvc_opal.c b/drivers/tty/hvc/hvc_opal.c index 47b54c6..b7cd0ae 100644 --- a/drivers/tty/hvc/hvc_opal.c +++ b/drivers/tty/hvc/hvc_opal.c @@ -224,6 +224,9 @@ static int hvc_opal_probe(struct platform_device *dev) hp = hvc_alloc(termno, irq, ops, MAX_VIO_PUT_CHARS); if (IS_ERR(hp)) return PTR_ERR(hp); + + /* hvc consoles on powernv may need to share a single irq */ + hp->flags = IRQF_SHARED; dev_set_drvdata(&dev->dev, hp); return 0;
Commit 2def86a7200c ("hvc: Convert to using interrupts instead of opal events") enabled the use of interrupts in the hvc_driver for OPAL platforms. However on machines with more than one hvc console, any console after the first will fail to register an interrupt handler in notifier_add_irq() since all consoles share the same IRQ number but do not set the IRQF_SHARED flag: [ 51.179907] genirq: Flags mismatch irq 31. 00000000 (hvc_console) vs. 00000000 (hvc_console) [ 51.180010] hvc_open: request_irq failed with rc -16. This error propagates up to hvc_open() and the console is closed, but OPAL will still generate interrupts that are not handled, leading to rcu_sched stall warnings. Set IRQF_SHARED when calling request_irq, allowing additional consoles to start properly. This is only set for consoles handled by hvc_opal_probe(), leaving other types unaffected. Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com> Cc: <stable@vger.kernel.org> # 4.1.x- --- drivers/tty/hvc/hvc_console.h | 1 + drivers/tty/hvc/hvc_irq.c | 7 +++++-- drivers/tty/hvc/hvc_opal.c | 3 +++ 3 files changed, 9 insertions(+), 2 deletions(-)