Re: [PATCH 09/20] drm/i915/power: use generic poll_timeout_us() instead of wait_for()

["Hogander, Jouni" <jouni.hogander@intel.com>]

On Thu, 2025-08-28 at 15:20 +0300, Jani Nikula wrote:
> Prefer generic poll helpers over i915 custom helpers.
> 
> The functional change is losing the exponentially growing sleep of
> wait_for(), which used to be 10, 20, 40, ..., 640, and 1280 us.
> 
> Use an arbitrary constant 100 us sleep instead. The timeout remains
> at 1
> ms.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_display_power.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c
> b/drivers/gpu/drm/i915/display/intel_display_power.c
> index d1d3b6f89e2a..7340d5a71673 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> @@ -3,6 +3,7 @@
>   * Copyright © 2019 Intel Corporation
>   */
>  
> +#include <linux/iopoll.h>
>  #include <linux/string_helpers.h>
>  
>  #include "soc/intel_dram.h"
> @@ -1310,8 +1311,10 @@ static void hsw_disable_lcpll(struct
> intel_display *display,
>  	hsw_write_dcomp(display, val);
>  	ndelay(100);
>  
> -	if (wait_for((hsw_read_dcomp(display) &
> -		      D_COMP_RCOMP_IN_PROGRESS) == 0, 1))
> +	ret = poll_timeout_us(val = hsw_read_dcomp(display),
> +			      (val & D_COMP_RCOMP_IN_PROGRESS) == 0,
> +			      100, 1000, false);
> +	if (ret)
>  		drm_err(display->drm, "D_COMP RCOMP still in
> progress\n");
>  
>  	if (allow_power_down) {