drm/udl: Refactor edid retrieving in UDL driver (v2)

Now drm/udl driver uses drm_do_get_edid() function to retrieve and
validate all blocks of EDID data. Old approach had insufficient
validation routine and had problems with retrieving of extra blocks

Signed-off-by: Robert Tarasov <tutankhamen@chromium.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
[airlied: Fix spelling mistakes]
Link: https://patchwork.freedesktop.org/patch/msgid/20190314225339.162386-1-tutankhamen@chromium.org

diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c
index 66885c2..c1bd5e3 100644 (file)
--- a/drivers/gpu/drm/udl/udl_connector.c
+++ b/drivers/gpu/drm/udl/udl_connector.c
@@ -18,18 +18,19 @@
 #include "udl_connector.h"
 #include "udl_drv.h"
 
-static bool udl_get_edid_block(struct udl_device *udl, int block_idx,
-                                                          u8 *buff)
+static int udl_get_edid_block(void *data, u8 *buf, unsigned int block,
+                              size_t len)
 {
        int ret, i;
        u8 *read_buff;
+       struct udl_device *udl = data;
 
        read_buff = kmalloc(2, GFP_KERNEL);
        if (!read_buff)
-               return false;
+               return -1;
 
-       for (i = 0; i < EDID_LENGTH; i++) {
-               int bval = (i + block_idx * EDID_LENGTH) << 8;
+       for (i = 0; i < len; i++) {
+               int bval = (i + block * EDID_LENGTH) << 8;
                ret = usb_control_msg(udl->udev,
                                      usb_rcvctrlpipe(udl->udev, 0),
                                          (0x02), (0x80 | (0x02 << 5)), bval,
@@ -37,60 +38,13 @@ static bool udl_get_edid_block(struct udl_device *udl, int block_idx,
                if (ret < 1) {
                        DRM_ERROR("Read EDID byte %d failed err %x\n", i, ret);
                        kfree(read_buff);
-                       return false;
+                       return -1;
                }
-               buff[i] = read_buff[1];
+               buf[i] = read_buff[1];
        }
 
        kfree(read_buff);
-       return true;
-}
-
-static bool udl_get_edid(struct udl_device *udl, u8 **result_buff,
-                        int *result_buff_size)
-{
-       int i, extensions;
-       u8 *block_buff = NULL, *buff_ptr;
-
-       block_buff = kmalloc(EDID_LENGTH, GFP_KERNEL);
-       if (block_buff == NULL)
-               return false;
-
-       if (udl_get_edid_block(udl, 0, block_buff) &&
-           memchr_inv(block_buff, 0, EDID_LENGTH)) {
-               extensions = ((struct edid *)block_buff)->extensions;
-               if (extensions > 0) {
-                       /* we have to read all extensions one by one */
-                       *result_buff_size = EDID_LENGTH * (extensions + 1);
-                       *result_buff = kmalloc(*result_buff_size, GFP_KERNEL);
-                       buff_ptr = *result_buff;
-                       if (buff_ptr == NULL) {
-                               kfree(block_buff);
-                               return false;
-                       }
-                       memcpy(buff_ptr, block_buff, EDID_LENGTH);
-                       kfree(block_buff);
-                       buff_ptr += EDID_LENGTH;
-                       for (i = 1; i < extensions; ++i) {
-                               if (udl_get_edid_block(udl, i, buff_ptr)) {
-                                       buff_ptr += EDID_LENGTH;
-                               } else {
-                                       kfree(*result_buff);
-                                       *result_buff = NULL;
-                                       return false;
-                               }
-                       }
-                       return true;
-               }
-               /* we have only base edid block */
-               *result_buff = block_buff;
-               *result_buff_size = EDID_LENGTH;
-               return true;
-       }
-
-       kfree(block_buff);
-
-       return false;
+       return 0;
 }
 
 static int udl_get_modes(struct drm_connector *connector)
@@ -122,8 +76,6 @@ static enum drm_mode_status udl_mode_valid(struct drm_connector *connector,
 static enum drm_connector_status
 udl_detect(struct drm_connector *connector, bool force)
 {
-       u8 *edid_buff = NULL;
-       int edid_buff_size = 0;
        struct udl_device *udl = connector->dev->dev_private;
        struct udl_drm_connector *udl_connector =
                                        container_of(connector,
@@ -136,12 +88,10 @@ udl_detect(struct drm_connector *connector, bool force)
                udl_connector->edid = NULL;
        }
 
-
-       if (!udl_get_edid(udl, &edid_buff, &edid_buff_size))
+       udl_connector->edid = drm_do_get_edid(connector, udl_get_edid_block, udl);
+       if (!udl_connector->edid)
                return connector_status_disconnected;
 
-       udl_connector->edid = (struct edid *)edid_buff;
-       
        return connector_status_connected;
 }