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drm/i915: rework reading pipe disable fuses

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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: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190625175437.14840-3-lucas.demarchi@intel.com
This commit is contained in:
Lucas De Marchi
2019-06-25 10:54:11 -07:00
parent 7218524d3e
commit 501ec325f1
1 changed files with 13 additions and 23 deletions
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36
drivers/gpu/drm/i915/intel_device_info.c
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@@ -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 */