| Message ID | 1458262483-15149-1-git-send-email-sam@mendozajonas.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
Samuel Mendoza-Jonas <sam@mendozajonas.com> writes: > 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. > > Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com> > Cc: <stable@vger.kernel.org> # 4.1.x- Tested on 4.4.6 - seemed to stop (some of) the problems I was having when using it as a kernel for the bootloader on a FSP based POWER8 system. Tested-by: Stewart Smith <stewart@linux.vnet.ibm.com>
diff --git a/drivers/tty/hvc/hvc_irq.c b/drivers/tty/hvc/hvc_irq.c index c9adb05..621263a 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; } @@ -28,7 +31,7 @@ int notifier_add_irq(struct hvc_struct *hp, int irq) hp->irq_requested = 0; return 0; } - rc = request_irq(irq, hvc_handle_interrupt, 0, + rc = request_irq(irq, hvc_handle_interrupt, IRQF_SHARED, "hvc_console", hp); if (!rc) hp->irq_requested = 1;
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. Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com> Cc: <stable@vger.kernel.org> # 4.1.x- --- drivers/tty/hvc/hvc_irq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)