Re: [PATCH v3 4/4] drm/i915/dg2: Implement Wa_14022698537

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 30 Oct 2024, Raag Jadav <raag.jadav@intel.com> wrote:
> G8 power state entry is disabled due to a limitation on DG2, so we
> enable it from driver with Wa_14022698537. For now we enable it for
> all DG2 devices with the exception of a few, for which, we enable
> only when paired with whitelisted CPU models. This works with Native
> ASMP and reduces idle power consumption.
>
> $ echo powersave > /sys/module/pcie_aspm/parameters/policy
> $ lspci -s 0000:03:00.0 -vvv
> LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk-
>
> v2: Fix Wa_ID and include it in subject (Badal)
>     Rephrase commit message (Jani)
> v3: Move workaround to i915_pcode_init() (Badal, Anshuman)
>     Re-order macro (Riana)
>
> Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_driver.c | 15 +++++++++++++++
>  drivers/gpu/drm/i915/i915_reg.h    |  1 +
>  2 files changed, 16 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> index 365329ff8a07..59c6124c9bc2 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -93,12 +93,14 @@
>  #include "i915_memcpy.h"
>  #include "i915_perf.h"
>  #include "i915_query.h"
> +#include "i915_reg.h"
>  #include "i915_suspend.h"
>  #include "i915_switcheroo.h"
>  #include "i915_sysfs.h"
>  #include "i915_utils.h"
>  #include "i915_vgpu.h"
>  #include "intel_clock_gating.h"
> +#include "intel_cpu_info.h"
>  #include "intel_gvt.h"
>  #include "intel_memory_region.h"
>  #include "intel_pci_config.h"
> @@ -415,6 +417,18 @@ static int i915_set_dma_info(struct drm_i915_private *i915)
>  	return ret;
>  }
>  
> +/* Wa_14022698537:dg2 */
> +static void i915_enable_g8(struct drm_i915_private *i915)
> +{
> +	if (IS_DG2(i915)) {
> +		if (IS_DG2_D(i915) && !intel_match_g8_cpu())
> +			return;

You don't need to check for DG2 twice.

BR,
Jani.

> +
> +		snb_pcode_write_p(&i915->uncore, PCODE_POWER_SETUP,
> +				  POWER_SETUP_SUBCOMMAND_G8_ENABLE, 0, 0);
> +	}
> +}
> +
>  static int i915_pcode_init(struct drm_i915_private *i915)
>  {
>  	struct intel_gt *gt;
> @@ -428,6 +442,7 @@ static int i915_pcode_init(struct drm_i915_private *i915)
>  		}
>  	}
>  
> +	i915_enable_g8(i915);
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 89e4381f8baa..d400c77423a5 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3617,6 +3617,7 @@
>  #define	    POWER_SETUP_I1_WATTS		REG_BIT(31)
>  #define	    POWER_SETUP_I1_SHIFT		6	/* 10.6 fixed point format */
>  #define	    POWER_SETUP_I1_DATA_MASK		REG_GENMASK(15, 0)
> +#define     POWER_SETUP_SUBCOMMAND_G8_ENABLE	0x6
>  #define GEN12_PCODE_READ_SAGV_BLOCK_TIME_US	0x23
>  #define   XEHP_PCODE_FREQUENCY_CONFIG		0x6e	/* pvc */
>  /* XEHP_PCODE_FREQUENCY_CONFIG sub-commands (param1) */

-- 
Jani Nikula, Intel