On 10/21/2017 06:41 PM, Jerry Hoemann wrote:
On Fri, Oct 20, 2017 at 07:25:20PM -0700, Guenter Roeck wrote:
On 10/20/2017 03:54 PM, Jerry Hoemann wrote:
Add support for WDIOC_GETPRETIMEOUT ioctl so that user applications
can determine when the NMI should arrive.
Signed-off-by: Jerry Hoemann <[email protected]>
---
drivers/watchdog/hpwdt.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
index 67fbe35..ef54b03 100644
--- a/drivers/watchdog/hpwdt.c
+++ b/drivers/watchdog/hpwdt.c
@@ -50,6 +50,7 @@
static bool nowayout = WATCHDOG_NOWAYOUT;
static char expect_release;
static unsigned long hpwdt_is_open;
+static const int pretimeout = 9;
static void __iomem *pci_mem_addr; /* the PCI-memory address */
static unsigned long __iomem *hpwdt_timer_reg;
@@ -622,6 +623,12 @@ static long hpwdt_ioctl(struct file *file, unsigned int
cmd,
}
break;
+ case WDIOC_GETPRETIMEOUT:
+ ret = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
+ if (ret)
+ ret = -EFAULT;
+ break;
+
case WDIOC_SETTIMEOUT:
ret = get_user(new_margin, p);
if (ret)
Can you please convert the driver to use the watchdog subsystem instead ?
If there are still improvements needed afterwards, they can still be
implemented, but we really should not make improvements which are
already supported by the watchdog core.
I will look into converting the driver, but would like to get this
fix in independently.
I don't see this patch as a fix. It adds functionality. the other two patches
are fixes and should come first.
SuSE brought https://bugzilla.novell.com/show_bug.cgi?id=1042933
to my attention earlier this summer. The submitter was trying to
develop a watchdog test where the ping rate was set to be the
Timeout/2.
The test worked fine until (Timeout/2) < PreTimeout. At this point
an NMI would be delivered to the system before the test could refresh
the timer.
Yes, but I don't think that is fixed with this patch. That would be patch 3/3,
no ?
Guenter
I came to the view that a watchdog that implements a pre-timeout NMI
where the value of the pre-timeout is not known programmatically as having
a defect.
This problem has been around a long time and we could live with it, but
figured while I was in fixing other problems, I'd fix this one as well.
Thanks
