On Fri, 29 May 2026, Ville Syrjala <[email protected]> wrote:
> From: Ville Syrjälä <[email protected]>
>
> Currently any "slow" wait will first try a "fast" wait
> with a 2 usec timeout, and then fall back to whatever
> timeout was specified originally. The "slow" wait will
> anyway start off with a mere 10 usec polling interval,
> so basically we can only save 8 usec with the "fast" wait
> (maybe a bit more given hrtimer setup costs etc.).
>
> I don't think we really do any operations in the display
> code where that kinds of 8 usec saving would be meaningful.
> So just get rid of the whole "fast" wait complication and
> go straight for the "slow" wait.
>
> Signed-off-by: Ville Syrjälä <[email protected]>

I think the whole fast/slow thing is just echoes from the old i915 wait
helpers.

Reviewed-by: Jani Nikula <[email protected]>

> ---
>  drivers/gpu/drm/i915/display/intel_de.c | 40 ++++++-------------------
>  1 file changed, 9 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_de.c 
> b/drivers/gpu/drm/i915/display/intel_de.c
> index 6daee9e82503..a7417905192d 100644
> --- a/drivers/gpu/drm/i915/display/intel_de.c
> +++ b/drivers/gpu/drm/i915/display/intel_de.c
> @@ -9,11 +9,11 @@
>  
>  #include "intel_de.h"
>  
> -static int __intel_de_wait_for_register(struct intel_display *display,
> -                                     intel_reg_t reg, u32 mask, u32 value,
> -                                     unsigned int timeout_us,
> -                                     u32 (*read)(struct intel_display 
> *display, intel_reg_t reg),
> -                                     u32 *out_val, bool is_atomic)
> +static int intel_de_wait_for_register(struct intel_display *display,
> +                                   intel_reg_t reg, u32 mask, u32 value,
> +                                   unsigned int timeout_us,
> +                                   u32 (*read)(struct intel_display 
> *display, intel_reg_t reg),
> +                                   u32 *out_val, bool is_atomic)
>  {
>       const ktime_t end = ktime_add_us(ktime_get_raw(), timeout_us);
>       int wait_max = 1000;
> @@ -60,28 +60,6 @@ static int __intel_de_wait_for_register(struct 
> intel_display *display,
>       return ret;
>  }
>  
> -static int intel_de_wait_for_register(struct intel_display *display,
> -                                   intel_reg_t reg, u32 mask, u32 value,
> -                                   unsigned int fast_timeout_us,
> -                                   unsigned int slow_timeout_us,
> -                                   u32 (*read)(struct intel_display 
> *display, intel_reg_t reg),
> -                                   u32 *out_value, bool is_atomic)
> -{
> -     int ret = -EINVAL;
> -
> -     if (fast_timeout_us)
> -             ret = __intel_de_wait_for_register(display, reg, mask, value,
> -                                                fast_timeout_us, read,
> -                                                out_value, is_atomic);
> -
> -     if (ret && slow_timeout_us)
> -             ret = __intel_de_wait_for_register(display, reg, mask, value,
> -                                                slow_timeout_us, read,
> -                                                out_value, is_atomic);
> -
> -     return ret;
> -}
> -
>  int intel_de_wait_us(struct intel_display *display, intel_reg_t reg,
>                    u32 mask, u32 value, unsigned int timeout_us,
>                    u32 *out_value)
> @@ -91,7 +69,7 @@ int intel_de_wait_us(struct intel_display *display, 
> intel_reg_t reg,
>       intel_dmc_wl_get(display, reg);
>  
>       ret = intel_de_wait_for_register(display, reg, mask, value,
> -                                      timeout_us, 0,
> +                                      timeout_us,
>                                        intel_de_read,
>                                        out_value, false);
>  
> @@ -109,7 +87,7 @@ int intel_de_wait_ms(struct intel_display *display, 
> intel_reg_t reg,
>       intel_dmc_wl_get(display, reg);
>  
>       ret = intel_de_wait_for_register(display, reg, mask, value,
> -                                      2, timeout_ms * 1000,
> +                                      timeout_ms * 1000,
>                                        intel_de_read,
>                                        out_value, false);
>  
> @@ -123,7 +101,7 @@ int intel_de_wait_fw_ms(struct intel_display *display, 
> intel_reg_t reg,
>                       u32 *out_value)
>  {
>       return intel_de_wait_for_register(display, reg, mask, value,
> -                                       2, timeout_ms * 1000,
> +                                       timeout_ms * 1000,
>                                         intel_de_read_fw,
>                                         out_value, false);
>  }
> @@ -133,7 +111,7 @@ int intel_de_wait_fw_us_atomic(struct intel_display 
> *display, intel_reg_t reg,
>                              u32 *out_value)
>  {
>       return intel_de_wait_for_register(display, reg, mask, value,
> -                                       timeout_us, 0,
> +                                       timeout_us,
>                                         intel_de_read_fw,
>                                         out_value, true);
>  }

-- 
Jani Nikula, Intel

Reply via email to