Potential fix for bug 5393 - KMSDRM: using atomic mode setting breaks…

… GPU compatibility Substring I was trying the KMSDRM video backend with some very simple programs that were working ok on 2.0.12. The same code won?t work on the current dev branch and I get: DEBUG: check_modesetting: probing ?/dev/dri/card0? DEBUG: /dev/dri/card0 connector, encoder and CRTC counts are: 4 5 6 DEBUG: check_modesetting: probing ?/dev/dri/card0? DEBUG: /dev/dri/card0 connector, encoder and CRTC counts are: 4 5 6 DEBUG: KMSDRM_VideoInit() DEBUG: Opening device /dev/dri/card0 DEBUG: Opened DRM FD (3) DEBUG: no atomic modesetting support. DEBUG: Video subsystem has not been initialized INFO: Using SDL video driver: (null) DEBUG: Video subsystem has not been initialized After carefully checking, the radeon driver doesn?t support atomic modesetting. That?s not the only problem : the same happens with the amdgpu driver if we disable Display Core (kernel parameter amdgpu.dc=0, which is required to get analogue outputs working). This is a major regression in the KMSDRM driver. Using atomic mode setting is great, but having no fallback to the "standard KMS" is bad.
libsdl-org · Dec 15, 2020 · f883928 · f883928
1 parent c02d88d
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diff --git a/cmake/sdlchecks.cmake b/cmake/sdlchecks.cmake
@@ -1163,7 +1163,8 @@ macro(CheckKMSDRM)
       set(HAVE_SDL_VIDEO TRUE)
 
       file(GLOB KMSDRM_SOURCES ${SDL2_SOURCE_DIR}/src/video/kmsdrm/*.c)
-      set(SOURCE_FILES ${SOURCE_FILES} ${KMSDRM_SOURCES})
+      file(GLOB KMSDRM_LEGACY_SOURCES ${SDL2_SOURCE_DIR}/src/video/kmsdrm_legacy/*.c)
+      set(SOURCE_FILES ${SOURCE_FILES} ${KMSDRM_SOURCES} ${KMSDRM_LEGACY_SOURCES})
 
       list(APPEND EXTRA_CFLAGS ${KMSDRM_CFLAGS})
 

diff --git a/configure b/configure
@@ -22119,6 +22119,7 @@ fi
 $as_echo "#define SDL_VIDEO_DRIVER_KMSDRM 1" >>confdefs.h
 
             SOURCES="$SOURCES $srcdir/src/video/kmsdrm/*.c"
+            SOURCES="$SOURCES $srcdir/src/video/kmsdrm_legacy/*.c"
             EXTRA_CFLAGS="$EXTRA_CFLAGS $LIBDRM_CFLAGS $LIBGBM_CFLAGS"
 
             { $as_echo "$as_me:${as_lineno-$LINENO}: checking for kmsdrm dynamic loading support" >&5

diff --git a/configure.ac b/configure.ac
@@ -2253,6 +2253,7 @@ AS_HELP_STRING([--enable-kmsdrm-shared], [dynamically load kmsdrm support [[defa
 
             AC_DEFINE(SDL_VIDEO_DRIVER_KMSDRM, 1, [ ])
             SOURCES="$SOURCES $srcdir/src/video/kmsdrm/*.c"
+            SOURCES="$SOURCES $srcdir/src/video/kmsdrm_legacy/*.c"
             EXTRA_CFLAGS="$EXTRA_CFLAGS $LIBDRM_CFLAGS $LIBGBM_CFLAGS"
 
             AC_MSG_CHECKING(for kmsdrm dynamic loading support)

diff --git a/src/video/SDL_sysvideo.h b/src/video/SDL_sysvideo.h
@@ -429,6 +429,7 @@ extern VideoBootStrap Android_bootstrap;
 extern VideoBootStrap PSP_bootstrap;
 extern VideoBootStrap RPI_bootstrap;
 extern VideoBootStrap KMSDRM_bootstrap;
+extern VideoBootStrap KMSDRM_LEGACY_bootstrap;
 extern VideoBootStrap DUMMY_bootstrap;
 extern VideoBootStrap Wayland_bootstrap;
 extern VideoBootStrap NACL_bootstrap;

diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
@@ -96,6 +96,7 @@ static VideoBootStrap *bootstrap[] = {
 #endif
 #if SDL_VIDEO_DRIVER_KMSDRM
     &KMSDRM_bootstrap,
+    &KMSDRM_LEGACY_bootstrap,
 #endif
 #if SDL_VIDEO_DRIVER_RPI
     &RPI_bootstrap,

diff --git a/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_dyn.c b/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_dyn.c
@@ -0,0 +1,167 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "../../SDL_internal.h"
+
+#if SDL_VIDEO_DRIVER_KMSDRM
+
+#define DEBUG_DYNAMIC_KMSDRM_LEGACY 0
+
+#include "SDL_kmsdrm_legacy_dyn.h"
+
+#ifdef SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC
+
+#include "SDL_name.h"
+#include "SDL_loadso.h"
+
+typedef struct
+{
+    void *lib;
+    const char *libname;
+} kmsdrmdynlib;
+
+#ifndef SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC
+#define SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC NULL
+#endif
+#ifndef SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC_GBM
+#define SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC_GBM NULL
+#endif
+
+static kmsdrmdynlib kmsdrmlibs[] = {
+    {NULL, SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC_GBM},
+    {NULL, SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC}
+};
+
+static void *
+KMSDRM_LEGACY_GetSym(const char *fnname, int *pHasModule)
+{
+    int i;
+    void *fn = NULL;
+    for (i = 0; i < SDL_TABLESIZE(kmsdrmlibs); i++) {
+        if (kmsdrmlibs[i].lib != NULL) {
+            fn = SDL_LoadFunction(kmsdrmlibs[i].lib, fnname);
+            if (fn != NULL)
+                break;
+        }
+    }
+
+#if DEBUG_DYNAMIC_KMSDRM_LEGACY
+    if (fn != NULL)
+        SDL_Log("KMSDRM_LEGACY: Found '%s' in %s (%p)\n", fnname, kmsdrmlibs[i].libname, fn);
+    else
+        SDL_Log("KMSDRM_LEGACY: Symbol '%s' NOT FOUND!\n", fnname);
+#endif
+
+    if (fn == NULL)
+        *pHasModule = 0;  /* kill this module. */
+
+    return fn;
+}
+
+#endif /* SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC */
+
+/* Define all the function pointers and wrappers... */
+#define SDL_KMSDRM_LEGACY_MODULE(modname) int SDL_KMSDRM_HAVE_##modname = 0;
+#define SDL_KMSDRM_LEGACY_SYM(rc,fn,params) SDL_DYNKMSDRMFN_##fn KMSDRM_##fn = NULL;
+#define SDL_KMSDRM_LEGACY_SYM_CONST(type,name) SDL_DYNKMSDRMCONST_##name KMSDRM_##name = NULL;
+#include "SDL_kmsdrm_legacy_sym.h"
+
+static int kmsdrm_load_refcount = 0;
+
+void
+SDL_KMSDRM_LEGACY_UnloadSymbols(void)
+{
+    /* Don't actually unload if more than one module is using the libs... */
+    if (kmsdrm_load_refcount > 0) {
+        if (--kmsdrm_load_refcount == 0) {
+#ifdef SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC
+            int i;
+#endif
+
+            /* set all the function pointers to NULL. */
+#define SDL_KMSDRM_LEGACY_MODULE(modname) SDL_KMSDRM_HAVE_##modname = 0;
+#define SDL_KMSDRM_LEGACY_SYM(rc,fn,params) KMSDRM_##fn = NULL;
+#define SDL_KMSDRM_LEGACY_SYM_CONST(type,name) KMSDRM_##name = NULL;
+#include "SDL_kmsdrm_legacy_sym.h"
+
+
+#ifdef SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC
+            for (i = 0; i < SDL_TABLESIZE(kmsdrmlibs); i++) {
+                if (kmsdrmlibs[i].lib != NULL) {
+                    SDL_UnloadObject(kmsdrmlibs[i].lib);
+                    kmsdrmlibs[i].lib = NULL;
+                }
+            }
+#endif
+        }
+    }
+}
+
+/* returns non-zero if all needed symbols were loaded. */
+int
+SDL_KMSDRM_LEGACY_LoadSymbols(void)
+{
+    int rc = 1;                 /* always succeed if not using Dynamic KMSDRM_LEGACY stuff. */
+
+    /* deal with multiple modules needing these symbols... */
+    if (kmsdrm_load_refcount++ == 0) {
+#ifdef SDL_VIDEO_DRIVER_KMSDRM_DYNAMIC
+        int i;
+        int *thismod = NULL;
+        for (i = 0; i < SDL_TABLESIZE(kmsdrmlibs); i++) {
+            if (kmsdrmlibs[i].libname != NULL) {
+                kmsdrmlibs[i].lib = SDL_LoadObject(kmsdrmlibs[i].libname);
+            }
+        }
+
+#define SDL_KMSDRM_LEGACY_MODULE(modname) SDL_KMSDRM_HAVE_##modname = 1; /* default yes */
+#include "SDL_kmsdrm_legacy_sym.h"
+
+#define SDL_KMSDRM_LEGACY_MODULE(modname) thismod = &SDL_KMSDRM_HAVE_##modname;
+#define SDL_KMSDRM_LEGACY_SYM(rc,fn,params) KMSDRM_##fn = (SDL_DYNKMSDRMFN_##fn) KMSDRM_GetSym(#fn,thismod);
+#define SDL_KMSDRM_LEGACY_SYM_CONST(type,name) KMSDRM_##name = *(SDL_DYNKMSDRMCONST_##name*) KMSDRM_GetSym(#name,thismod);
+#include "SDL_kmsdrm_legacy_sym.h"
+
+        if ((SDL_KMSDRM_LEGACY_HAVE_LIBDRM) && (SDL_KMSDRM_HAVE_GBM)) {
+            /* all required symbols loaded. */
+            SDL_ClearError();
+        } else {
+            /* in case something got loaded... */
+            SDL_KMSDRM_LEGACY_UnloadSymbols();
+            rc = 0;
+        }
+
+#else  /* no dynamic KMSDRM_LEGACY */
+
+#define SDL_KMSDRM_LEGACY_MODULE(modname) SDL_KMSDRM_HAVE_##modname = 1; /* default yes */
+#define SDL_KMSDRM_LEGACY_SYM(rc,fn,params) KMSDRM_##fn = fn;
+#define SDL_KMSDRM_LEGACY_SYM_CONST(type,name) KMSDRM_##name = name;
+#include "SDL_kmsdrm_legacy_sym.h"
+
+#endif
+    }
+
+    return rc;
+}
+
+#endif /* SDL_VIDEO_DRIVER_KMSDRM */
+
+/* vi: set ts=4 sw=4 expandtab: */
diff --git a/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_dyn.h b/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_dyn.h
@@ -0,0 +1,53 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef SDL_kmsdrmdyn_h_
+#define SDL_kmsdrmdyn_h_
+
+#include "../../SDL_internal.h"
+
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+#include <gbm.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int SDL_KMSDRM_LEGACY_LoadSymbols(void);
+void SDL_KMSDRM_LEGACY_UnloadSymbols(void);
+
+/* Declare all the function pointers and wrappers... */
+#define SDL_KMSDRM_LEGACY_SYM(rc,fn,params) \
+    typedef rc (*SDL_DYNKMSDRM_LEGACYFN_##fn) params; \
+    extern SDL_DYNKMSDRM_LEGACYFN_##fn KMSDRM_##fn;
+#define SDL_KMSDRM_LEGACY_SYM_CONST(type, name) \
+    typedef type SDL_DYNKMSDRM_LEGACYCONST_##name; \
+    extern SDL_DYNKMSDRM_LEGACYCONST_##name KMSDRM_##name;
+#include "SDL_kmsdrm_legacy_sym.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SDL_kmsdrmdyn_h_ */
+
+/* vi: set ts=4 sw=4 expandtab: */
diff --git a/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_events.c b/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_events.c
@@ -0,0 +1,42 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "../../SDL_internal.h"
+
+#if SDL_VIDEO_DRIVER_KMSDRM
+
+#include "SDL_kmsdrm_legacy_video.h"
+#include "SDL_kmsdrm_legacy_events.h"
+
+#ifdef SDL_INPUT_LINUXEV
+#include "../../core/linux/SDL_evdev.h"
+#endif
+
+void KMSDRM_LEGACY_PumpEvents(_THIS)
+{
+#ifdef SDL_INPUT_LINUXEV
+    SDL_EVDEV_Poll();
+#endif
+
+}
+
+#endif /* SDL_VIDEO_DRIVER_KMSDRM */
+
diff --git a/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_events.h b/src/video/kmsdrm_legacy/SDL_kmsdrm_legacy_events.h
@@ -0,0 +1,31 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "../../SDL_internal.h"
+
+#ifndef SDL_kmsdrmevents_h_
+#define SDL_kmsdrmevents_h_
+
+extern void KMSDRM_LEGACY_PumpEvents(_THIS);
+extern void KMSDRM_LEGACY_EventInit(_THIS);
+extern void KMSDRM_LEGACY_EventQuit(_THIS);
+
+#endif /* SDL_kmsdrmevents_h_ */