Re: [Intel-gfx] [PATCH v2 1/1] drm/i915/mtl: Disable MC6 for MTL A step

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Mar 10, 2023 at 11:43:39AM +0530, Badal Nilawar wrote:
> The Wa_14017073508 require to send Media Busy/Idle mailbox while
> accessing Media tile. As of now it is getting handled while __gt_unpark,
> __gt_park. But there are various corner cases where forcewakes are taken
> without __gt_unpark i.e. without sending Busy Mailbox especially during
> register reads. Forcewakes are taken without busy mailbox leads to
> GPU HANG. So bringing mailbox calls under forcewake calls are no feasible
> option as forcewake calls are atomic and mailbox calls are blocking.
> The issue already fixed in B step so disabling MC6 on A step and
> reverting previous commit which handles Wa_14017073508
> 
> Fixes: 8f70f1ec587d ("drm/i915/mtl: Add Wa_14017073508 for SAMedia")
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

I confirm my rv-b here although this came from a combination of 2 patches
and has a different msg.

However, depending on when we got the CI results back I won't be
available for pushing it and I will be out next week. I hope another
committer can push this to drm-intel-gt-next.

BTW, no need for cover letter in single patches.

Thanks for the patch,
Rodrigo.

> ---
>  drivers/gpu/drm/i915/gt/intel_gt_pm.c     | 27 -----------------------
>  drivers/gpu/drm/i915/gt/intel_rc6.c       |  8 +++++++
>  drivers/gpu/drm/i915/gt/uc/intel_guc_rc.c | 13 +----------
>  drivers/gpu/drm/i915/i915_reg.h           |  9 --------
>  4 files changed, 9 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> index 85ae7dc079f2..e02cb90723ae 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> @@ -20,31 +20,10 @@
>  #include "intel_rc6.h"
>  #include "intel_rps.h"
>  #include "intel_wakeref.h"
> -#include "intel_pcode.h"
>  #include "pxp/intel_pxp_pm.h"
>  
>  #define I915_GT_SUSPEND_IDLE_TIMEOUT (HZ / 2)
>  
> -static void mtl_media_busy(struct intel_gt *gt)
> -{
> -	/* Wa_14017073508: mtl */
> -	if (IS_MTL_GRAPHICS_STEP(gt->i915, P, STEP_A0, STEP_B0) &&
> -	    gt->type == GT_MEDIA)
> -		snb_pcode_write_p(gt->uncore, PCODE_MBOX_GT_STATE,
> -				  PCODE_MBOX_GT_STATE_MEDIA_BUSY,
> -				  PCODE_MBOX_GT_STATE_DOMAIN_MEDIA, 0);
> -}
> -
> -static void mtl_media_idle(struct intel_gt *gt)
> -{
> -	/* Wa_14017073508: mtl */
> -	if (IS_MTL_GRAPHICS_STEP(gt->i915, P, STEP_A0, STEP_B0) &&
> -	    gt->type == GT_MEDIA)
> -		snb_pcode_write_p(gt->uncore, PCODE_MBOX_GT_STATE,
> -				  PCODE_MBOX_GT_STATE_MEDIA_NOT_BUSY,
> -				  PCODE_MBOX_GT_STATE_DOMAIN_MEDIA, 0);
> -}
> -
>  static void user_forcewake(struct intel_gt *gt, bool suspend)
>  {
>  	int count = atomic_read(&gt->user_wakeref);
> @@ -92,9 +71,6 @@ static int __gt_unpark(struct intel_wakeref *wf)
>  
>  	GT_TRACE(gt, "\n");
>  
> -	/* Wa_14017073508: mtl */
> -	mtl_media_busy(gt);
> -
>  	/*
>  	 * It seems that the DMC likes to transition between the DC states a lot
>  	 * when there are no connected displays (no active power domains) during
> @@ -144,9 +120,6 @@ static int __gt_park(struct intel_wakeref *wf)
>  	GEM_BUG_ON(!wakeref);
>  	intel_display_power_put_async(i915, POWER_DOMAIN_GT_IRQ, wakeref);
>  
> -	/* Wa_14017073508: mtl */
> -	mtl_media_idle(gt);
> -
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/gt/intel_rc6.c b/drivers/gpu/drm/i915/gt/intel_rc6.c
> index 5c91622dfca4..f4150f61f39c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rc6.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rc6.c
> @@ -486,6 +486,7 @@ static bool bxt_check_bios_rc6_setup(struct intel_rc6 *rc6)
>  static bool rc6_supported(struct intel_rc6 *rc6)
>  {
>  	struct drm_i915_private *i915 = rc6_to_i915(rc6);
> +	struct intel_gt *gt = rc6_to_gt(rc6);
>  
>  	if (!HAS_RC6(i915))
>  		return false;
> @@ -502,6 +503,13 @@ static bool rc6_supported(struct intel_rc6 *rc6)
>  		return false;
>  	}
>  
> +	if (IS_MTL_MEDIA_STEP(gt->i915, STEP_A0, STEP_B0) &&
> +	    gt->type == GT_MEDIA) {
> +		drm_notice(&i915->drm,
> +			   "Media RC6 disabled on A step\n");
> +		return false;
> +	}
> +
>  	return true;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_rc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_rc.c
> index fcf51614f9a4..1adec6de223c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_rc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_rc.c
> @@ -12,20 +12,9 @@
>  
>  static bool __guc_rc_supported(struct intel_guc *guc)
>  {
> -	struct intel_gt *gt = guc_to_gt(guc);
> -
> -	/*
> -	 * Wa_14017073508: mtl
> -	 * Do not enable gucrc to avoid additional interrupts which
> -	 * may disrupt pcode wa.
> -	 */
> -	if (IS_MTL_GRAPHICS_STEP(gt->i915, P, STEP_A0, STEP_B0) &&
> -	    gt->type == GT_MEDIA)
> -		return false;
> -
>  	/* GuC RC is unavailable for pre-Gen12 */
>  	return guc->submission_supported &&
> -		GRAPHICS_VER(gt->i915) >= 12;
> +		GRAPHICS_VER(guc_to_gt(guc)->i915) >= 12;
>  }
>  
>  static bool __guc_rc_selected(struct intel_guc *guc)
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index b9b6d46dfe1b..9db6b3f06a74 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6460,15 +6460,6 @@
>  /*   XEHP_PCODE_FREQUENCY_CONFIG param2 */
>  #define     PCODE_MBOX_DOMAIN_NONE		0x0
>  #define     PCODE_MBOX_DOMAIN_MEDIAFF		0x3
> -
> -/* Wa_14017210380: mtl */
> -#define   PCODE_MBOX_GT_STATE			0x50
> -/* sub-commands (param1) */
> -#define     PCODE_MBOX_GT_STATE_MEDIA_BUSY	0x1
> -#define     PCODE_MBOX_GT_STATE_MEDIA_NOT_BUSY	0x2
> -/* param2 */
> -#define     PCODE_MBOX_GT_STATE_DOMAIN_MEDIA	0x1
> -
>  #define GEN6_PCODE_DATA				_MMIO(0x138128)
>  #define   GEN6_PCODE_FREQ_IA_RATIO_SHIFT	8
>  #define   GEN6_PCODE_FREQ_RING_RATIO_SHIFT	16
> -- 
> 2.25.1
>