[Intel-gfx] [PATCH] drm/i915: User POSTING_READ and I915_READ_NOTRACE in lcpll code

[Paulo Zanoni]

2013/8/21 Daniel Vetter <daniel.vetter at ffwll.ch>:
> If we don't use the return value of a mmio read our coding style is to
> use the POSTING_READ macro. This avoids cluttering the mmio traces.
>
> Similarly for busy loops to wait for a bit to flip we use the _NOTRACE
> variant to avoid filling up the tracebuffers with gunk. Spotted while
> reading some follow-up patches from Paulo.
>
> While at it add the missing posting read in the lcpll enable function
> that Paulo spotted.
>
> Cc: Paulo Zanoni <przanoni at gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

I'm pretty sure I added many other wait_for calls without the _NOTRACE
in the past...

> ---
>  drivers/gpu/drm/i915/intel_display.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 7a40427..39b53e5 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -5999,7 +5999,7 @@ void hsw_disable_lcpll(struct drm_i915_private *dev_priv,
>         I915_WRITE(LCPLL_CTL, val);
>         POSTING_READ(LCPLL_CTL);
>
> -       if (wait_for((I915_READ(LCPLL_CTL) & LCPLL_PLL_LOCK) == 0, 1))
> +       if (wait_for((I915_READ_NOTRACE(LCPLL_CTL) & LCPLL_PLL_LOCK) == 0, 1))
>                 DRM_ERROR("LCPLL still locked\n");
>
>         val = I915_READ(D_COMP);
> @@ -6008,7 +6008,7 @@ void hsw_disable_lcpll(struct drm_i915_private *dev_priv,
>         POSTING_READ(D_COMP);
>         ndelay(100);
>
> -       if (wait_for((I915_READ(D_COMP) & D_COMP_RCOMP_IN_PROGRESS) == 0, 1))
> +       if (wait_for((I915_READ_NOTRACE(D_COMP) & D_COMP_RCOMP_IN_PROGRESS) == 0, 1))
>                 DRM_ERROR("D_COMP RCOMP still in progress\n");
>
>         if (allow_power_down) {
> @@ -6036,19 +6036,20 @@ void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
>         if (val & LCPLL_POWER_DOWN_ALLOW) {
>                 val &= ~LCPLL_POWER_DOWN_ALLOW;
>                 I915_WRITE(LCPLL_CTL, val);
> +               POSTING_READ(LCPLL_CTL);
>         }
>
>         val = I915_READ(D_COMP);
>         val |= D_COMP_COMP_FORCE;
>         val &= ~D_COMP_COMP_DISABLE;
>         I915_WRITE(D_COMP, val);
> -       I915_READ(D_COMP);
> +       POSTING_READ(D_COMP);
>
>         val = I915_READ(LCPLL_CTL);
>         val &= ~LCPLL_PLL_DISABLE;
>         I915_WRITE(LCPLL_CTL, val);
>
> -       if (wait_for(I915_READ(LCPLL_CTL) & LCPLL_PLL_LOCK, 5))
> +       if (wait_for(I915_READ_NOTRACE(LCPLL_CTL) & LCPLL_PLL_LOCK, 5))
>                 DRM_ERROR("LCPLL not locked yet\n");
>
>         if (val & LCPLL_CD_SOURCE_FCLK) {
> @@ -6056,7 +6057,7 @@ void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
>                 val &= ~LCPLL_CD_SOURCE_FCLK;
>                 I915_WRITE(LCPLL_CTL, val);
>
> -               if (wait_for_atomic_us((I915_READ(LCPLL_CTL) &
> +               if (wait_for_atomic_us((I915_READ_NOTRACE(LCPLL_CTL) &
>                                         LCPLL_CD_SOURCE_FCLK_DONE) == 0, 1))
>                         DRM_ERROR("Switching back to LCPLL failed\n");
>         }
> --
> 1.8.4.rc3
>



-- 
Paulo Zanoni