[RFC PATCH 121/162] drm/i915: WA for zero memory channel

[Matthew Auld]

From: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

Commit c457d9cf256e ("drm/i915: Make sure we have enough memory
bandwidth on ICL") assumes that we always have a non-zero
dram_info->channels and uses it as a divisor. We need num memory
channels to be at least 1 for sane bw limits checking, even when PCode
returns 0, so lets force it to 1 in this case.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
---
 drivers/gpu/drm/i915/display/intel_bw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_bw.c b/drivers/gpu/drm/i915/display/intel_bw.c
index bd060404d249..9e7971ce24b3 100644
--- a/drivers/gpu/drm/i915/display/intel_bw.c
+++ b/drivers/gpu/drm/i915/display/intel_bw.c
@@ -222,7 +222,7 @@ static int icl_get_bw_info(struct drm_i915_private *dev_priv, const struct intel
 			    "Failed to get memory subsystem information, ignoring bandwidth limits");
 		return ret;
 	}
-	num_channels = qi.num_channels;
+	num_channels = max_t(u8, 1, qi.num_channels);
 
 	deinterleave = DIV_ROUND_UP(num_channels, is_y_tile ? 4 : 2);
 	dclk_max = icl_sagv_max_dclk(&qi);
-- 
2.26.2