#include "i915_drv.h"
 #include "intel_guc_ct.h"
 
+#ifdef CONFIG_DRM_I915_DEBUG_GUC
+#define CT_DEBUG_DRIVER(...)   DRM_DEBUG_DRIVER(__VA_ARGS__)
+#else
+#define CT_DEBUG_DRIVER(...)   do { } while (0)
+#endif
+
 struct ct_request {
        struct list_head link;
        u32 fence;
 static void guc_ct_buffer_desc_init(struct guc_ct_buffer_desc *desc,
                                    u32 cmds_addr, u32 size, u32 owner)
 {
-       DRM_DEBUG_DRIVER("CT: desc %p init addr=%#x size=%u owner=%u\n",
-                        desc, cmds_addr, size, owner);
+       CT_DEBUG_DRIVER("CT: desc %p init addr=%#x size=%u owner=%u\n",
+                       desc, cmds_addr, size, owner);
        memset(desc, 0, sizeof(*desc));
        desc->addr = cmds_addr;
        desc->size = size;
 
 static void guc_ct_buffer_desc_reset(struct guc_ct_buffer_desc *desc)
 {
-       DRM_DEBUG_DRIVER("CT: desc %p reset head=%u tail=%u\n",
-                        desc, desc->head, desc->tail);
+       CT_DEBUG_DRIVER("CT: desc %p reset head=%u tail=%u\n",
+                       desc, desc->head, desc->tail);
        desc->head = 0;
        desc->tail = 0;
        desc->is_in_error = 0;
                err = PTR_ERR(blob);
                goto err_vma;
        }
-       DRM_DEBUG_DRIVER("CT: vma base=%#x\n",
-                        intel_guc_ggtt_offset(guc, ctch->vma));
+       CT_DEBUG_DRIVER("CT: vma base=%#x\n",
+                       intel_guc_ggtt_offset(guc, ctch->vma));
 
        /* store pointers to desc and cmds */
        for (i = 0; i < ARRAY_SIZE(ctch->ctbs); i++) {
 err_vma:
        i915_vma_unpin_and_release(&ctch->vma);
 err_out:
-       DRM_DEBUG_DRIVER("CT: channel %d initialization failed; err=%d\n",
-                        ctch->owner, err);
+       CT_DEBUG_DRIVER("CT: channel %d initialization failed; err=%d\n",
+                       ctch->owner, err);
        return err;
 }
 
        int err;
        int i;
 
-       DRM_DEBUG_DRIVER("CT: channel %d reopen=%s\n",
-                        ctch->owner, yesno(ctch_is_open(ctch)));
+       CT_DEBUG_DRIVER("CT: channel %d reopen=%s\n",
+                       ctch->owner, yesno(ctch_is_open(ctch)));
 
        if (!ctch->vma) {
                err = ctch_init(guc, ctch);
                 (want_response ? GUC_CT_MSG_SEND_STATUS : 0) |
                 (action[0] << GUC_CT_MSG_ACTION_SHIFT);
 
+       CT_DEBUG_DRIVER("CT: writing %*phn %*phn %*phn\n",
+                       4, &header, 4, &fence,
+                       4 * (len - 1), &action[1]);
+
        cmds[tail] = header;
        tail = (tail + 1) % size;
 
        if (unlikely(ret < 0)) {
                DRM_ERROR("CT: send action %#X failed; err=%d status=%#X\n",
                          action[0], ret, status);
+       } else if (unlikely(ret)) {
+               CT_DEBUG_DRIVER("CT: send action %#x returned %d (%#x)\n",
+                               action[0], ret, ret);
        }
 
        mutex_unlock(&guc->send_mutex);
        /* beware of buffer wrap case */
        if (unlikely(available < 0))
                available += size;
+       CT_DEBUG_DRIVER("CT: available %d (%u:%u)\n", available, head, tail);
        GEM_BUG_ON(available < 0);
 
        data[0] = cmds[head];
                data[i] = cmds[head];
                head = (head + 1) % size;
        }
+       CT_DEBUG_DRIVER("CT: received %*phn\n", 4 * len, data);
 
        desc->head = head * 4;
        return 0;
                return -EPROTO;
        }
 
+       CT_DEBUG_DRIVER("CT: response fence %u status %#x\n", fence, status);
+
        spin_lock(&ct->lock);
        list_for_each_entry(req, &ct->pending_requests, link) {
                if (unlikely(fence != req->fence)) {
-                       DRM_DEBUG_DRIVER("CT: request %u awaits response\n",
-                                        req->fence);
+                       CT_DEBUG_DRIVER("CT: request %u awaits response\n",
+                                       req->fence);
                        continue;
                }
                if (unlikely(datalen > req->response_len)) {
 {
        struct intel_guc *guc = ct_to_guc(ct);
 
+       CT_DEBUG_DRIVER("CT: request %x %*phn\n", action, 4 * len, payload);
+
        switch (action) {
        case INTEL_GUC_ACTION_DEFAULT:
                if (unlikely(len < 1))