[PATCH] drm/radeon/kms/pm: bail early if nothing's changing

[Alex Deucher]

On Fri, Aug 13, 2010 at 10:53 AM, Alex Deucher <alexdeucher at gmail.com> wrote:
> If we aren't changing the power state, no need to take
> locks and schedule fences, etc.
>
> There seem to be lock ordering issues in the CP and
> fence code in some cases; see bug 29140 below.
>
> Fixes:
> https://bugs.freedesktop.org/show_bug.cgi?id=29140
> Possibly also:
> https://bugzilla.kernel.org/show_bug.cgi?id=16581

Also fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=29384

Alex

>
> Signed-off-by: Alex Deucher <alexdeucher at gmail.com>
> Cc: stable at kernel.org
> ---
>  drivers/gpu/drm/radeon/radeon_pm.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
> index a3d25f4..9a8031b 100644
> --- a/drivers/gpu/drm/radeon/radeon_pm.c
> +++ b/drivers/gpu/drm/radeon/radeon_pm.c
> @@ -226,6 +226,11 @@ static void radeon_pm_set_clocks(struct radeon_device *rdev)
>  {
>        int i;
>
> +       /* no need to take locks, etc. if nothing's going to change */
> +       if ((rdev->pm.requested_clock_mode_index == rdev->pm.current_clock_mode_index) &&
> +           (rdev->pm.requested_power_state_index == rdev->pm.current_power_state_index))
> +               return;
> +
>        mutex_lock(&rdev->ddev->struct_mutex);
>        mutex_lock(&rdev->vram_mutex);
>        mutex_lock(&rdev->cp.mutex);
> --
> 1.7.1.1
>
>