Improve KMS debuggability and avoid known broken cases

src/platform/linux/kmsgrab.cpp

@@ -15,6 +15,7 @@
 #include <filesystem>
 #include <thread>
 
+#include "src/config.h"
 #include "src/logging.h"
 #include "src/platform/common.h"
 #include "src/round_robin.h"
@@ -298,6 +299,9 @@ namespace platf {
           return -1;
         }
 
+        version_t ver { drmGetVersion(fd.el) };
+        BOOST_LOG(info) << path << " -> "sv << ((ver && ver->name) ? ver->name : "UNKNOWN");
+
         // Open the render node for this card to share with libva.
         // If it fails, we'll just share the primary node instead.
         char *rendernode_path = drmGetRenderDeviceNameFromFd(fd.el);
@@ -316,12 +320,21 @@ namespace platf {
         }
 
         if (drmSetClientCap(fd.el, DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1)) {
-          BOOST_LOG(error) << "Couldn't expose some/all drm planes for card: "sv << path;
+          BOOST_LOG(error) << "GPU driver doesn't support universal planes: "sv << path;
           return -1;
         }
 
         if (drmSetClientCap(fd.el, DRM_CLIENT_CAP_ATOMIC, 1)) {
-          BOOST_LOG(warning) << "Couldn't expose some properties for card: "sv << path;
+          BOOST_LOG(warning) << "GPU driver doesn't support atomic mode-setting: "sv << path;
+#if defined(SUNSHINE_BUILD_X11)
+          // We won't be able to capture the mouse cursor with KMS on non-atomic drivers,
+          // so fall back to X11 if it's available and the user didn't explicitly force KMS.
+          if (window_system == window_system_e::X11 && config::video.capture != "kms") {
+            BOOST_LOG(info) << "Avoiding KMS capture under X11 due to lack of atomic mode-setting"sv;
+            return -1;
+          }
+#endif
+          BOOST_LOG(warning) << "Cursor capture may fail without atomic mode-setting support!"sv;
         }
 
         plane_res.reset(drmModeGetPlaneResources(fd.el));
@@ -640,8 +653,7 @@ namespace platf {
             }
 
             if (!fb->handles[0]) {
-              BOOST_LOG(error)
-                << "Couldn't get handle for DRM Framebuffer ["sv << plane->fb_id << "]: Possibly not permitted: do [sudo setcap cap_sys_admin+p sunshine]"sv;
+              BOOST_LOG(error) << "Couldn't get handle for DRM Framebuffer ["sv << plane->fb_id << "]: Probably not permitted"sv;
               return -1;
             }
 
@@ -909,12 +921,14 @@ namespace platf {
 
         if (!prop_crtc_w || !prop_crtc_h || !prop_crtc_x || !prop_crtc_y) {
           BOOST_LOG(error) << "Cursor plane is missing required plane CRTC properties!"sv;
+          BOOST_LOG(error) << "Atomic mode-setting must be enabled to capture the cursor!"sv;
           cursor_plane_id = -1;
           captured_cursor.visible = false;
           return;
         }
         if (!prop_src_x || !prop_src_y || !prop_src_w || !prop_src_h) {
           BOOST_LOG(error) << "Cursor plane is missing required plane SRC properties!"sv;
+          BOOST_LOG(error) << "Atomic mode-setting must be enabled to capture the cursor!"sv;
           cursor_plane_id = -1;
           captured_cursor.visible = false;
           return;
@@ -1072,8 +1086,7 @@ namespace platf {
         }
 
         if (!fb->handles[0]) {
-          BOOST_LOG(error)
-            << "Couldn't get handle for DRM Framebuffer ["sv << plane->fb_id << "]: Possibly not permitted: do [sudo setcap cap_sys_admin+p sunshine]"sv;
+          BOOST_LOG(error) << "Couldn't get handle for DRM Framebuffer ["sv << plane->fb_id << "]: Probably not permitted"sv;
           return capture_e::error;
         }
 
@@ -1647,8 +1660,9 @@ namespace platf {
         }
 
         if (!fb->handles[0]) {
-          BOOST_LOG(error)
-            << "Couldn't get handle for DRM Framebuffer ["sv << plane->fb_id << "]: Possibly not permitted: do [sudo setcap cap_sys_admin+p sunshine]"sv;
+          BOOST_LOG(error) << "Couldn't get handle for DRM Framebuffer ["sv << plane->fb_id << "]: Probably not permitted"sv;
+          BOOST_LOG((window_system != window_system_e::X11 || config::video.capture == "kms") ? fatal : error)
+            << "You must run [sudo setcap cap_sys_admin+p $(readlink -f sunshine)] for KMS display capture to work!"sv;
           break;
         }