Commit 501ec325 authored by Lucas De Marchi's avatar Lucas De Marchi
Browse files

drm/i915: rework reading pipe disable fuses 



This prepares to have possibly more than 3 pipes. I didn't want to
continue the previous approach since the check for "are the disabled
pipes the last ones" poses a combinatory explosion. We need that check
because in several places of the code we have that assumption. If that
ever becomes false in a new HW, other parts of the code would have to
change.

Now we start by considering we have info->num_pipes enabled and disable
each pipe that is marked as disabled. Then it's a simple matter of
checking if we have at least one pipe and that all the enabled ones are
the first pipes, i.e. there are no holes in the bitmask.

Cc: Jose Souza <jose.souza@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190625175437.14840-3-lucas.demarchi@intel.com
parent 7218524d

drivers/gpu/drm/i915/intel_device_info.c

+13 −23
Original line number Diff line number Diff line
@@ -929,35 +929,25 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv) 
		}

	} else if (HAS_DISPLAY(dev_priv) && INTEL_GEN(dev_priv) >= 9) {

		u32 dfsm = I915_READ(SKL_DFSM);

		u8 disabled_mask = 0;

		bool invalid;

		int num_bits;

		u8 enabled_mask = BIT(info->num_pipes) - 1;



		if (dfsm & SKL_DFSM_PIPE_A_DISABLE)

			disabled_mask |= BIT(PIPE_A);

			enabled_mask &= ~BIT(PIPE_A);

		if (dfsm & SKL_DFSM_PIPE_B_DISABLE)

			disabled_mask |= BIT(PIPE_B);

			enabled_mask &= ~BIT(PIPE_B);

		if (dfsm & SKL_DFSM_PIPE_C_DISABLE)

			disabled_mask |= BIT(PIPE_C);

			enabled_mask &= ~BIT(PIPE_C);



		num_bits = hweight8(disabled_mask);



		switch (disabled_mask) {

		case BIT(PIPE_A):

		case BIT(PIPE_B):

		case BIT(PIPE_A) | BIT(PIPE_B):

		case BIT(PIPE_A) | BIT(PIPE_C):

			invalid = true;

			break;

		default:

			invalid = false;

		}



		if (num_bits > info->num_pipes || invalid)

			DRM_ERROR("invalid pipe fuse configuration: 0x%x\n",

				  disabled_mask);

		/*

		 * At least one pipe should be enabled and if there are

		 * disabled pipes, they should be the last ones, with no holes

		 * in the mask.

		 */

		if (enabled_mask == 0 || !is_power_of_2(enabled_mask + 1))

			DRM_ERROR("invalid pipe fuse configuration: enabled_mask=0x%x\n",

				  enabled_mask);

		else

			info->num_pipes -= num_bits;

			info->num_pipes = hweight8(enabled_mask);

	}



	/* Initialize slice/subslice/EU info */