From b69bf1a6acf5f1e3fe6d71f5cf1bf77d16fa8083 Mon Sep 17 00:00:00 2001
From: Christopher Michael <devilhorns@comcast.net>
Date: Wed, 17 Aug 2022 12:22:10 -0400
Subject: [PATCH] ecore_drm2: Add check for Atomic Modesetting support

---
 src/lib/ecore_drm2/ecore_drm2.c         |  2 ++
 src/lib/ecore_drm2/ecore_drm2_device.c  | 29 ++++++++++++++++++++++++-
 src/lib/ecore_drm2/ecore_drm2_private.h |  4 ++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/lib/ecore_drm2/ecore_drm2.c b/src/lib/ecore_drm2/ecore_drm2.c
index 6d1096d2b7..2ae711fcc7 100644
--- a/src/lib/ecore_drm2/ecore_drm2.c
+++ b/src/lib/ecore_drm2/ecore_drm2.c
@@ -10,6 +10,7 @@ int _ecore_drm2_log_dom = -1;
 /* external drm function prototypes (for dlopen) */
 void *(*sym_drmModeGetResources)(int fd) = NULL;
 void (*sym_drmModeFreeResources)(drmModeResPtr ptr) = NULL;
+int (*sym_drmSetClientCap)(int fd, uint64_t capability, uint64_t value) = NULL;
 
 /* local static functions */
 static Eina_Bool
@@ -46,6 +47,7 @@ _ecore_drm2_link(void)
         /* TODO: Sym needed libdrm functions */
         SYM(_drm_lib, drmModeGetResources);
         SYM(_drm_lib, drmModeFreeResources);
+        SYM(_drm_lib, drmSetClientCap);
 
         if (fail)
           {
diff --git a/src/lib/ecore_drm2/ecore_drm2_device.c b/src/lib/ecore_drm2/ecore_drm2_device.c
index 6396c92d5e..2fb0311e22 100644
--- a/src/lib/ecore_drm2/ecore_drm2_device.c
+++ b/src/lib/ecore_drm2/ecore_drm2_device.c
@@ -1,6 +1,25 @@
 #include "ecore_drm2_private.h"
 
+/* external variable for using atomic */
+Eina_Bool _ecore_drm2_atomic_use = EINA_FALSE;
+
 /* local functions */
+static Eina_Bool
+_ecore_drm2_device_atomic_capable_get(int fd)
+{
+   Eina_Bool ret = EINA_TRUE;
+
+   if (sym_drmSetClientCap(fd, DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1) < 0)
+     ret = EINA_FALSE;
+   else
+     {
+        if (sym_drmSetClientCap(fd, DRM_CLIENT_CAP_ATOMIC, 1) < 0)
+          ret = EINA_FALSE;
+     }
+
+   return ret;
+}
+
 static Eina_Bool
 _ecore_drm2_device_modeset_capable_get(int fd)
 {
@@ -124,7 +143,15 @@ ecore_drm2_device_open(const char *seat, unsigned int tty)
         goto open_err;
      }
 
-   /* TODO: elput_input_init, check atomic capable, etc */
+   /* TODO: elput_input_init, etc */
+
+   /* NB: For now, we will ONLY support Atomic */
+   _ecore_drm2_atomic_use = _ecore_drm2_device_atomic_capable_get(dev->fd);
+   if (!_ecore_drm2_atomic_use)
+     {
+        WRN("Could not enable Atomic Modesetting support");
+        goto open_err;
+     }
 
    return dev;
 
diff --git a/src/lib/ecore_drm2/ecore_drm2_private.h b/src/lib/ecore_drm2/ecore_drm2_private.h
index 3f336e3070..06f53fb0d2 100644
--- a/src/lib/ecore_drm2/ecore_drm2_private.h
+++ b/src/lib/ecore_drm2/ecore_drm2_private.h
@@ -31,6 +31,9 @@
 /* define necessary vars/macros for ecore_drm2 log domain */
 extern int _ecore_drm2_log_dom;
 
+/* define externval variable for atomic */
+extern Eina_Bool _ecore_drm2_atomic_use;
+
 # ifdef ECORE_DRM2_DEFAULT_LOG_COLOR
 #  undef ECORE_DRM2_DEFAULT_LOG_COLOR
 # endif
@@ -72,5 +75,6 @@ struct _Ecore_Drm2_Device
 /* external drm function prototypes (for dlopen) */
 extern void *(*sym_drmModeGetResources)(int fd);
 extern void (*sym_drmModeFreeResources)(drmModeResPtr ptr);
+extern int (*sym_drmSetClientCap)(int fd, uint64_t capability, uint64_t value);
 
 #endif