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-rw-r--r--libdrm/xf86drmMode.c39
1 files changed, 32 insertions, 7 deletions
diff --git a/libdrm/xf86drmMode.c b/libdrm/xf86drmMode.c
index 872604ff..e2aba810 100644
--- a/libdrm/xf86drmMode.c
+++ b/libdrm/xf86drmMode.c
@@ -357,21 +357,45 @@ drmModeConnectorPtr drmModeGetConnector(int fd, uint32_t connector_id)
{
struct drm_mode_get_connector conn;
drmModeConnectorPtr r = NULL;
+ int pre_props = 8, pre_modes = 16, pre_encoders = 4;
conn.connector_id = connector_id;
conn.connector_type_id = 0;
conn.connector_type = 0;
- conn.count_modes = 0;
- conn.modes_ptr = 0;
- conn.count_props = 0;
- conn.props_ptr = 0;
- conn.prop_values_ptr = 0;
- conn.count_encoders = 0;
- conn.encoders_ptr = 0;
+ conn.count_modes = pre_modes;
+ conn.count_props = pre_props;
+ conn.count_encoders = pre_encoders;
+
+ /*
+ * Pre-allocate space for some modes, properties, and encoders. If
+ * we're lucky we won't need to call into the kernel twice.
+ */
+ conn.props_ptr = VOID2U64(drmMalloc(pre_props * sizeof(uint32_t)));
+ conn.prop_values_ptr = VOID2U64(drmMalloc(pre_props *
+ sizeof(uint64_t)));
+ conn.modes_ptr = VOID2U64(drmMalloc(pre_modes *
+ sizeof(struct drm_mode_modeinfo)));
+ conn.encoders_ptr = VOID2U64(drmMalloc(pre_encoders *
+ sizeof(uint32_t)));
if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn))
return 0;
+ if (conn.count_props <= pre_props &&
+ conn.count_modes <= pre_modes &&
+ conn.count_encoders <= pre_encoders)
+ goto done;
+
+ /* Oh well, free & reallocate everything and ask again... */
+ drmFree(U642VOID(conn.prop_values_ptr));
+ drmFree(U642VOID(conn.props_ptr));
+ drmFree(U642VOID(conn.modes_ptr));
+ drmFree(U642VOID(conn.encoders_ptr));
+ conn.prop_values_ptr = 0;
+ conn.props_ptr = 0;
+ conn.modes_ptr = 0;
+ conn.encoders_ptr = 0;
+
if (conn.count_props) {
conn.props_ptr = VOID2U64(drmMalloc(conn.count_props*sizeof(uint32_t)));
conn.prop_values_ptr = VOID2U64(drmMalloc(conn.count_props*sizeof(uint64_t)));
@@ -386,6 +410,7 @@ drmModeConnectorPtr drmModeGetConnector(int fd, uint32_t connector_id)
if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn))
goto err_allocs;
+done:
if(!(r = drmMalloc(sizeof(*r)))) {
goto err_allocs;
}