[PATCH 6/8] drm/i915/histogram: histogram delay counter doesnt reset

[Kandpal, Suraj]

> -----Original Message-----
> From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Arun R
> Murthy
> Sent: Tuesday, November 19, 2024 4:15 PM
> To: intel-xe at lists.freedesktop.org; intel-gfx at lists.freedesktop.org; dri-
> devel at lists.freedesktop.org
> Cc: Murthy, Arun R <arun.r.murthy at intel.com>
> Subject: [PATCH 6/8] drm/i915/histogram: histogram delay counter doesnt
> reset
> 
> The delay counter for histogram does not reset and as a result the histogram
> bin never gets updated. Workaround would be to use save and restore
> histogram register.
> Wa: 14014889975

This should be above the Signed-off-by

> 
> Signed-off-by: Arun R Murthy <arun.r.murthy at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_histogram.c  | 17 +++++++++++++++++
> .../gpu/drm/i915/display/intel_histogram_regs.h |  1 +
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c
> b/drivers/gpu/drm/i915/display/intel_histogram.c
> index cba65f4260cd..fdcc64677e96 100644
> --- a/drivers/gpu/drm/i915/display/intel_histogram.c
> +++ b/drivers/gpu/drm/i915/display/intel_histogram.c
> @@ -74,6 +74,11 @@ static void intel_histogram_handle_int_work(struct
> work_struct *work)
>  	struct intel_display *display = to_intel_display(intel_crtc);
>  	char *histogram_event[] = {"HISTOGRAM=1", NULL};
> 
> +	/* Wa: 14014889975 */
> +	if (IS_DISPLAY_VER(display, 12, 13))

We have shifted to using is_display_verx100 so you can use that instead
Also there is no display ver 13 just 12 and then 14 so maybe this should be just display_ver == 12


> +		intel_de_rmw(display, DPST_CTL(intel_crtc->pipe),
> +			     DPST_CTL_RESTORE, 0);
> +
>  	/*
>  	 * TODO: PSR to be exited while reading the Histogram data
>  	 * Set DPST_CTL Bin Reg function select to TC @@ -94,6 +99,12 @@
> static void intel_histogram_handle_int_work(struct work_struct *work)
>  				"sending HISTOGRAM event failed\n");
>  	}
> 
> +	/* Wa: 14014889975 */
> +	if (IS_DISPLAY_VER(display, 12, 13))
> +		/* Write the value read from DPST_CTL to DPST_CTL.Interrupt
> Delay Counter(bit 23:16) */
> +		intel_de_write(display, DPST_CTL(intel_crtc->pipe),
> intel_de_read(display,
> +			       DPST_CTL(intel_crtc->pipe)) |
> DPST_CTL_RESTORE);
> +

>From the WA it seems we need to write 0 in the above Guardband Interrupt Delay Counter (bits 23:16) when servicing interrupts
And only write value read from dpst_ctl when enabling  dpst_config or doing an adjustment

Regards,
Suraj Kandpal

>  	/* Enable histogram interrupt */
>  	intel_de_rmw(display, DPST_GUARD(intel_crtc->pipe),
> DPST_GUARD_HIST_INT_EN,
>  		     DPST_GUARD_HIST_INT_EN);
> @@ -240,6 +251,12 @@ int intel_histogram_set_iet_lut(struct intel_crtc
> *intel_crtc, u32 *data)
>  		return -EINVAL;
>  	}
> 
> +	/* Wa: 14014889975 */
> +	if (IS_DISPLAY_VER(display, 12, 13))
> +		/* Write the value read from DPST_CTL to DPST_CTL.Interrupt
> Delay Counter(bit 23:16) */
> +		intel_de_write(display, DPST_CTL(intel_crtc->pipe),
> intel_de_read(display,
> +			       DPST_CTL(intel_crtc->pipe)) |
> DPST_CTL_RESTORE);
> +
>  	/*
>  	 * Set DPST_CTL Bin Reg function select to IE
>  	 * Set DPST_CTL Bin Register Index to 0 diff --git
> a/drivers/gpu/drm/i915/display/intel_histogram_regs.h
> b/drivers/gpu/drm/i915/display/intel_histogram_regs.h
> index 1252b4f339a6..e50b1448bd40 100644
> --- a/drivers/gpu/drm/i915/display/intel_histogram_regs.h
> +++ b/drivers/gpu/drm/i915/display/intel_histogram_regs.h
> @@ -16,6 +16,7 @@
>  #define  DPST_CTL_RESTORE				REG_BIT(28)
>  #define  DPST_CTL_IE_MODI_TABLE_EN			REG_BIT(27)
>  #define  DPST_CTL_HIST_MODE				REG_BIT(24)
> +#define  DPST_CTL_GUARDBAND_INTERRUPT_DELAY_CNT
> 	REG_GENMASK(23, 16)
>  #define  DPST_CTL_ENHANCEMENT_MODE_MASK
> 	REG_GENMASK(14, 13)
>  #define  DPST_CTL_EN_MULTIPLICATIVE
> 	REG_FIELD_PREP(DPST_CTL_ENHANCEMENT_MODE_MASK, 2)
>  #define  DPST_CTL_IE_TABLE_VALUE_FORMAT			REG_BIT(15)
> --
> 2.25.1