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    SubjectRe: [PATCH 1/2] watchdog: dw_wdt: Use a mutex, not a spinlock
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    Hi,

    On Thu, May 7, 2015 at 6:47 PM, Guenter Roeck <linux@roeck-us.net> wrote:
    > On 05/07/2015 03:09 PM, Doug Anderson wrote:
    >>
    >> Right now the dw_wdt uses a spinlock to protect dw_wdt_open(). The
    >> problem is that while holding the spinlock we call:
    >> -> dw_wdt_set_top()
    >> -> dw_wdt_top_in_seconds()
    >> -> clk_get_rate()
    >> -> clk_prepare_lock()
    >> -> mutex_lock()
    >>
    >> Locking a mutex while holding a spinlock is not allowed and leads to
    >> warnings like "BUG: spinlock wrong CPU on CPU#1", among other
    >> problems.
    >>
    >> There's no reason to use a spinlock, so switch to a mutex.
    >>
    >> Signed-off-by: Doug Anderson <dianders@chromium.org>
    >
    >
    > Reviewed-by: Guenter Roeck <linux@roeck-us.net>

    As Dmitry pointed out in another context, and even better fix is to
    just remove the spinlock altogether. I'll send up v2...

    -Doug


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