From 1c721962f46d30fdb46090b6b3b0e20d076bf825 Mon Sep 17 00:00:00 2001
From: Wanjohi <elviswanjohi47@gmail.com>
Date: Thu, 24 Sep 2026 16:42:16 +0300
Subject: [PATCH] fix(nescapture): put the masks in the DMA-BUF import failure
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"No suitable memory type for DMA-BUF import" names neither mask, so it cannot
tell a driver that refused the descriptor outright (fd_type_bits=0) from one
whose memory types simply do not overlap the image's — which are different
bugs in different components. The three numbers were already computed for a
debug! two lines above, and a debug line only fires at a level nobody runs in
the field; this one did not print at all while a neighbouring crate's did.

Now the failure carries image_type_bits, fd_type_bits, their intersection, and
the size, format, modifier and stride it was importing. On a virtualised NVIDIA
node this turned three unknowns into one measurement and pointed straight at
the kernel side.
---
 apps/nescapture/src/dmabuf_import.rs | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/apps/nescapture/src/dmabuf_import.rs b/apps/nescapture/src/dmabuf_import.rs
index 1d42394a..ba5adb47 100644
--- a/apps/nescapture/src/dmabuf_import.rs
+++ b/apps/nescapture/src/dmabuf_import.rs
@@ -199,7 +199,24 @@ impl DmaBufImporter {
         let memory_type_index = self
             .context
             .find_memory_type(memory_type_bits, vk::MemoryPropertyFlags::empty())
-            .ok_or_else(|| anyhow::anyhow!("No suitable memory type for DMA-BUF import"))?;
+            .ok_or_else(|| {
+                // The numbers, in the error rather than in the debug! above
+                // it: fd_type_bits=0 means the driver could not resolve the
+                // descriptor at all, which is a different fault from a
+                // mismatch, and the difference is the whole diagnosis.
+                anyhow::anyhow!(
+                    "No suitable memory type for DMA-BUF import: \
+                     image_type_bits={:#x} & fd_type_bits={:#x} = {:#x}, \
+                     size={}, format={:?}, modifier={:#x}, stride={}",
+                    mem_requirements.memory_type_bits,
+                    memory_fd_properties.memory_type_bits,
+                    memory_type_bits,
+                    mem_requirements.size,
+                    format,
+                    planes[0].modifier,
+                    planes[0].stride
+                )
+            })?;
 
         // Dedicated allocation (required by many drivers for external memory).
         let mut dedicated_alloc_info = vk::MemoryDedicatedAllocateInfo::default().image(image);