In commit b839a869dfc9 ("drm/i915/guc: Add support for data
reporting in GuC responses") we missed the hypothetical case
that GuC might return positive non-zero value as success data.

While that would be lucky treated as error case, and at the
end will result in reporting valid -EIO, in the meantime this
value will be passed to ERR_PTR that could be misleading.

v2: rebased

Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Michal Wajdeczko <[email protected]>
Cc: Dan Carpenter <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c 
b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
index 20c710a74498..c39abb010181 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
@@ -168,12 +168,15 @@ static int guc_action_register_ct_buffer(struct intel_guc 
*guc, u32 type,
                FIELD_PREP(HOST2GUC_REGISTER_CTB_REQUEST_MSG_2_DESC_ADDR, 
desc_addr),
                FIELD_PREP(HOST2GUC_REGISTER_CTB_REQUEST_MSG_3_BUFF_ADDR, 
buff_addr),
        };
+       int ret;
 
        GEM_BUG_ON(type != GUC_CTB_TYPE_HOST2GUC && type != 
GUC_CTB_TYPE_GUC2HOST);
        GEM_BUG_ON(size % SZ_4K);
 
        /* CT registration must go over MMIO */
-       return intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
+       ret = intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
+
+       return ret > 0 ? -EPROTO : ret;
 }
 
 static int ct_register_buffer(struct intel_guc_ct *ct, u32 type,
@@ -201,11 +204,14 @@ static int guc_action_deregister_ct_buffer(struct 
intel_guc *guc, u32 type)
                FIELD_PREP(GUC_HXG_REQUEST_MSG_0_ACTION, 
GUC_ACTION_HOST2GUC_DEREGISTER_CTB),
                FIELD_PREP(HOST2GUC_DEREGISTER_CTB_REQUEST_MSG_1_TYPE, type),
        };
+       int ret;
 
        GEM_BUG_ON(type != GUC_CTB_TYPE_HOST2GUC && type != 
GUC_CTB_TYPE_GUC2HOST);
 
        /* CT deregistration must go over MMIO */
-       return intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
+       ret = intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
+
+       return ret > 0 ? -EPROTO : ret;
 }
 
 static int ct_deregister_buffer(struct intel_guc_ct *ct, u32 type)
-- 
2.25.1

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