KMSDRM: Add gamma support

src/video/kmsdrm/SDL_kmsdrmsym.h

@@ -59,6 +59,10 @@ SDL_KMSDRM_SYM(drmModeCrtcPtr,drmModeGetCrtc,(int fd, uint32_t crtcId))
 SDL_KMSDRM_SYM(int,drmModeSetCrtc,(int fd, uint32_t crtcId, uint32_t bufferId,
                                    uint32_t x, uint32_t y, uint32_t *connectors, int count,
                                    drmModeModeInfoPtr mode))
+SDL_KMSDRM_SYM(int,drmModeCrtcGetGamma,(int fd, uint32_t crtc_id, uint32_t size,
+			                              uint16_t *red, uint16_t *green, uint16_t *blue))
+SDL_KMSDRM_SYM(int,drmModeCrtcSetGamma,(int fd, uint32_t crtc_id, uint32_t size,
+			                              uint16_t *red, uint16_t *green, uint16_t *blue))
 SDL_KMSDRM_SYM(int,drmModeSetCursor,(int fd, uint32_t crtcId, uint32_t bo_handle,
                                      uint32_t width, uint32_t height))
 SDL_KMSDRM_SYM(int,drmModeSetCursor2,(int fd, uint32_t crtcId, uint32_t bo_handle,

src/video/kmsdrm/SDL_kmsdrmvideo.c

@@ -243,6 +243,8 @@ KMSDRM_CreateDevice(int devindex)
     device->SetWindowPosition = KMSDRM_SetWindowPosition;
     device->SetWindowSize = KMSDRM_SetWindowSize;
     device->SetWindowFullscreen = KMSDRM_SetWindowFullscreen;
+    device->GetWindowGammaRamp = KMSDRM_GetWindowGammaRamp;
+    device->SetWindowGammaRamp = KMSDRM_SetWindowGammaRamp;
     device->ShowWindow = KMSDRM_ShowWindow;
     device->HideWindow = KMSDRM_HideWindow;
     device->RaiseWindow = KMSDRM_RaiseWindow;
@@ -1348,6 +1350,34 @@ KMSDRM_ReconfigureWindow( _THIS, SDL_Window * window) {
                         windata->surface_w, windata->surface_h);
 }
 
+int
+KMSDRM_GetWindowGammaRamp(_THIS, SDL_Window * window, Uint16 * ramp)
+{
+    SDL_WindowData *windata = (SDL_WindowData*)window->driverdata;
+    SDL_VideoData *viddata = (SDL_VideoData*)windata->viddata;
+    SDL_VideoDisplay *disp = SDL_GetDisplayForWindow(window);
+    SDL_DisplayData* dispdata = (SDL_DisplayData*)disp->driverdata;
+    if (KMSDRM_drmModeCrtcGetGamma(viddata->drm_fd, dispdata->crtc->crtc_id, 256, &ramp[0*256], &ramp[1*256], &ramp[2*256]) == -1)
+    {
+        return SDL_SetError("Failed to get gamma ramp");
+    }
+    return 0;
+}
+
+int
+KMSDRM_SetWindowGammaRamp(_THIS, SDL_Window * window, const Uint16 * ramp)
+{
+    SDL_WindowData *windata = (SDL_WindowData*)window->driverdata;
+    SDL_VideoData *viddata = (SDL_VideoData*)windata->viddata;
+    SDL_VideoDisplay *disp = SDL_GetDisplayForWindow(window);
+    SDL_DisplayData* dispdata = (SDL_DisplayData*)disp->driverdata;
+    if (KMSDRM_drmModeCrtcSetGamma(viddata->drm_fd, dispdata->crtc->crtc_id, 256, &ramp[0*256], &ramp[1*256], &ramp[2*256]) == -1)
+    {
+        return SDL_SetError("Failed to set gamma ramp");
+    }
+    return 0;
+}
+
 int
 KMSDRM_CreateWindowFrom(_THIS, SDL_Window * window, const void *data)
 {

src/video/kmsdrm/SDL_kmsdrmvideo.h

@@ -133,6 +133,8 @@ void KMSDRM_SetWindowIcon(_THIS, SDL_Window * window, SDL_Surface * icon);
 void KMSDRM_SetWindowPosition(_THIS, SDL_Window * window);
 void KMSDRM_SetWindowSize(_THIS, SDL_Window * window);
 void KMSDRM_SetWindowFullscreen(_THIS, SDL_Window * window, SDL_VideoDisplay * _display, SDL_bool fullscreen);
+int KMSDRM_SetWindowGammaRamp(_THIS, SDL_Window * window, const Uint16 * ramp);
+int KMSDRM_GetWindowGammaRamp(_THIS, SDL_Window * window, Uint16 * ramp);
 void KMSDRM_ShowWindow(_THIS, SDL_Window * window);
 void KMSDRM_HideWindow(_THIS, SDL_Window * window);
 void KMSDRM_RaiseWindow(_THIS, SDL_Window * window);