[PATCH v3 05/13] drm/i915/dmc: Add interface to block PKG C-state

[Kahola, Mika]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Jouni
> Högander
> Sent: Monday, 14 April 2025 13.05
> To: intel-gfx at lists.freedesktop.org; intel-xe at lists.freedesktop.org
> Cc: Hogander, Jouni <jouni.hogander at intel.com>
> Subject: [PATCH v3 05/13] drm/i915/dmc: Add interface to block PKG C-state
> 
> Add interface to block PKG C-state. This is needed to implement workaround for
> underrun on idle PSR HW issue (Wa_16025596647).
> 
> Bspec: 74151

Reviewed-by: Mika Kahola <mika.kahola at intel.com>

> Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dmc.c | 17 +++++++++++++++++
> drivers/gpu/drm/i915/display/intel_dmc.h |  2 ++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c
> b/drivers/gpu/drm/i915/display/intel_dmc.c
> index 98f80a6c63e8..c65544e48c42 100644
> --- a/drivers/gpu/drm/i915/display/intel_dmc.c
> +++ b/drivers/gpu/drm/i915/display/intel_dmc.c
> @@ -517,6 +517,23 @@ void intel_dmc_disable_pipe(struct intel_display
> *display, enum pipe pipe)
>  		intel_de_rmw(display, PIPEDMC_CONTROL(pipe),
> PIPEDMC_ENABLE, 0);  }
> 
> +/**
> + * intel_dmc_block_pkgc() - block PKG C-state
> + * @display: display instance
> + * @pipe: pipe which register use to block
> + * @block: block/unblock
> + *
> + * This interface is target for Wa_16025596647 usage. I.e. to set/clear
> + * PIPEDMC_BLOCK_PKGC_SW_BLOCK_PKGC_ALWAYS bit in
> PIPEDMC_BLOCK_PKGC_SW register.
> + */
> +void intel_dmc_block_pkgc(struct intel_display *display, enum pipe pipe,
> +			  bool block)
> +{
> +	intel_de_rmw(display, PIPEDMC_BLOCK_PKGC_SW(pipe),
> +		     PIPEDMC_BLOCK_PKGC_SW_BLOCK_PKGC_ALWAYS, block ?
> +		     PIPEDMC_BLOCK_PKGC_SW_BLOCK_PKGC_ALWAYS : 0); }
> +
>  static bool is_dmc_evt_ctl_reg(struct intel_display *display,
>  			       enum intel_dmc_id dmc_id, i915_reg_t reg)  { diff --
> git a/drivers/gpu/drm/i915/display/intel_dmc.h
> b/drivers/gpu/drm/i915/display/intel_dmc.h
> index c78426eb4cd5..236312fb791c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dmc.h
> +++ b/drivers/gpu/drm/i915/display/intel_dmc.h
> @@ -18,6 +18,8 @@ void intel_dmc_load_program(struct intel_display *display);
> void intel_dmc_disable_program(struct intel_display *display);  void
> intel_dmc_enable_pipe(struct intel_display *display, enum pipe pipe);  void
> intel_dmc_disable_pipe(struct intel_display *display, enum pipe pipe);
> +void intel_dmc_block_pkgc(struct intel_display *display, enum pipe pipe,
> +			  bool block);
>  void intel_dmc_fini(struct intel_display *display);  void intel_dmc_suspend(struct
> intel_display *display);  void intel_dmc_resume(struct intel_display *display);
> --
> 2.43.0