Re: [PATCH 05/12] drm/i915/mchbar: Use intel_mchbar_read() instead of intel_de_read()

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

On Wed, 25 Mar 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> We are doing a few accesses to MCHBAR registers with intel_de_read().
> Use the dedicated intel_mchbar_read() instead.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_cdclk.c         | 5 +++--
>  drivers/gpu/drm/i915/display/intel_display_power.c | 3 ++-
>  2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 121a12c5b8ac..2a17e9b22740 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -41,6 +41,7 @@
>  #include "intel_display_utils.h"
>  #include "intel_display_wa.h"
>  #include "intel_dram.h"
> +#include "intel_mchbar.h"
>  #include "intel_mchbar_regs.h"
>  #include "intel_parent.h"
>  #include "intel_pci_config.h"
> @@ -376,8 +377,8 @@ static unsigned int intel_hpll_vco(struct intel_display *display)
>  	else
>  		return 0;
>  
> -	tmp = intel_de_read(display, display->platform.pineview ||
> -			    display->platform.mobile ? HPLLVCO_MOBILE : HPLLVCO);
> +	tmp = intel_mchbar_read(display, display->platform.pineview ||
> +				display->platform.mobile ? HPLLVCO_MOBILE : HPLLVCO);
>  
>  	vco = vco_table[tmp & 0x7];
>  	if (vco == 0)
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
> index ec96b141c74c..8da2990395e0 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> @@ -24,6 +24,7 @@
>  #include "intel_display_wa.h"
>  #include "intel_dmc.h"
>  #include "intel_dram.h"
> +#include "intel_mchbar.h"
>  #include "intel_mchbar_regs.h"
>  #include "intel_parent.h"
>  #include "intel_pch_refclk.h"
> @@ -1252,7 +1253,7 @@ static void assert_can_disable_lcpll(struct intel_display *display)
>  static u32 hsw_read_dcomp(struct intel_display *display)
>  {
>  	if (display->platform.haswell)
> -		return intel_de_read(display, D_COMP_HSW);
> +		return intel_mchbar_read(display, D_COMP_HSW);
>  	else
>  		return intel_de_read(display, D_COMP_BDW);
>  }

-- 
Jani Nikula, Intel