[Intel-gfx] [PATCH 1/7] drm/i915: Remove the wait_for_us macro

[Daniel Vetter]

On Tue, May 17, 2016 at 06:43:22PM +0300, Mika Kuoppala wrote:
> We use jiffies based resolution for timeout detection. So
> the promise that in the event of timeout, we would return in the 1us
> resolution is false. And with quite large margin.
> 
> Remove the wait_for_us macro to prevent further broken promises
> and convert the 3 callsites. The wait time will grow to 1ms but
> this will be amended somewhat when wait_for gets enhanced with
> adaptive backoff.
> 
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> ---
>  drivers/gpu/drm/i915/intel_ddi.c     | 4 ++--
>  drivers/gpu/drm/i915/intel_display.c | 8 ++++----
>  drivers/gpu/drm/i915/intel_drv.h     | 1 -
>  3 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index c454744dda0b..a62c60c6fb0b 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1826,8 +1826,8 @@ static void broxton_phy_init(struct drm_i915_private *dev_priv,
>  	 * HW team confirmed that the time to reach phypowergood status is
>  	 * anywhere between 50 us and 100us.
>  	 */
> -	if (wait_for_us(((I915_READ(BXT_PORT_CL1CM_DW0(phy)) &
> -		(PHY_RESERVED | PHY_POWER_GOOD)) == PHY_POWER_GOOD), 100)) {
> +	if (wait_for(((I915_READ(BXT_PORT_CL1CM_DW0(phy)) &
> +		(PHY_RESERVED | PHY_POWER_GOOD)) == PHY_POWER_GOOD), 1)) {
>  		DRM_ERROR("timeout during PHY%d power on\n", phy);
>  	}
>  
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 4777087326f6..05d4a2b365f8 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -9619,8 +9619,8 @@ static void broadwell_set_cdclk(struct drm_device *dev, int cdclk)
>  	val |= LCPLL_CD_SOURCE_FCLK;
>  	I915_WRITE(LCPLL_CTL, val);
>  
> -	if (wait_for_us(I915_READ(LCPLL_CTL) &
> -			LCPLL_CD_SOURCE_FCLK_DONE, 1))
> +	if (wait_for(I915_READ(LCPLL_CTL) &
> +		     LCPLL_CD_SOURCE_FCLK_DONE, 1))
>  		DRM_ERROR("Switching to FCLK failed\n");
>  
>  	val = I915_READ(LCPLL_CTL);
> @@ -9654,8 +9654,8 @@ static void broadwell_set_cdclk(struct drm_device *dev, int cdclk)
>  	val &= ~LCPLL_CD_SOURCE_FCLK;
>  	I915_WRITE(LCPLL_CTL, val);
>  
> -	if (wait_for_us((I915_READ(LCPLL_CTL) &
> -			LCPLL_CD_SOURCE_FCLK_DONE) == 0, 1))
> +	if (wait_for((I915_READ(LCPLL_CTL) &
> +		      LCPLL_CD_SOURCE_FCLK_DONE) == 0, 1))
>  		DRM_ERROR("Switching back to LCPLL failed\n");
>  
>  	mutex_lock(&dev_priv->rps.hw_lock);
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 3536292babe0..0fc8579e7b2e 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -69,7 +69,6 @@
>  })
>  
>  #define wait_for(COND, MS)	  	_wait_for((COND), (MS) * 1000, 1000)
> -#define wait_for_us(COND, US)	  	_wait_for((COND), (US), 1)
>  
>  /* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */
>  #if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT)
> -- 
> 2.5.0
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch