• Mikulas Patocka's avatar
    cpufreq: speedstep-smi: enable interrupts when waiting · a3b6e7d4
    Mikulas Patocka authored
    commit d4d4eda2 upstream.
    
    On Dell Latitude C600 laptop with Pentium 3 850MHz processor, the
    speedstep-smi driver sometimes loads and sometimes doesn't load with
    "change to state X failed" message.
    
    The hardware sometimes refuses to change frequency and in this case, we
    need to retry later. I found out that we need to enable interrupts while
    waiting. When we enable interrupts, the hardware blockage that prevents
    frequency transition resolves and the transition is possible. With
    disabled interrupts, the blockage doesn't resolve (no matter how long do
    we wait). The exact reasons for this hardware behavior are unknown.
    
    This patch enables interrupts in the function speedstep_set_state that can
    be called with disabled interrupts. However, this function is called with
    disabled interrupts only from speedstep_get_freqs, so it shouldn't cause
    any problem.
    
    Signed-off-by: Mikulas Patocka <mpatocka@redhat.com
    Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
    a3b6e7d4
speedstep-lib.c 11.6 KB