4 files changed, 56 insertions, 2 deletions

diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c
index 7375353c04eb..b7a2fedc3904 100644
--- a/drivers/media/video/em28xx/em28xx-core.c
+++ b/drivers/media/video/em28xx/em28xx-core.c
@@ -1012,6 +1012,41 @@ int em28xx_init_isoc(struct em28xx *dev, int max_packets,
 }
 EXPORT_SYMBOL_GPL(em28xx_init_isoc);
 
+/* Determine the packet size for the DVB stream for the given device
+   (underlying value programmed into the eeprom) */
+int em28xx_isoc_dvb_max_packetsize(struct em28xx *dev)
+{
+        unsigned int chip_cfg2;
+        unsigned int packet_size = 564;
+
+        if (dev->chip_id == CHIP_ID_EM2874) {
+                /* FIXME - for now assume 564 like it was before, but the
+                   em2874 code should be added to return the proper value... */
+                packet_size = 564;
+        } else {
+                /* TS max packet size stored in bits 1-0 of R01 */
+                chip_cfg2 = em28xx_read_reg(dev, EM28XX_R01_CHIPCFG2);
+                switch (chip_cfg2 & EM28XX_CHIPCFG2_TS_PACKETSIZE_MASK) {
+                case EM28XX_CHIPCFG2_TS_PACKETSIZE_188:
+                        packet_size = 188;
+                        break;
+                case EM28XX_CHIPCFG2_TS_PACKETSIZE_376:
+                        packet_size = 376;
+                        break;
+                case EM28XX_CHIPCFG2_TS_PACKETSIZE_564:
+                        packet_size = 564;
+                        break;
+                case EM28XX_CHIPCFG2_TS_PACKETSIZE_752:
+                        packet_size = 752;
+                        break;
+                }
+        }
+
+        em28xx_coredbg("dvb max packet size=%d\n", packet_size);
+        return packet_size;
+}
+EXPORT_SYMBOL_GPL(em28xx_isoc_dvb_max_packetsize);
+
 /*
  * em28xx_wake_i2c()
  * configure i2c attached devices
diff --git a/drivers/media/video/em28xx/em28xx-dvb.c b/drivers/media/video/em28xx/em28xx-dvb.c
index c8188dc2b4b5..e0438acf1224 100644
--- a/drivers/media/video/em28xx/em28xx-dvb.c
+++ b/drivers/media/video/em28xx/em28xx-dvb.c
@@ -46,7 +46,6 @@ if (debug >= level) 						\
 } while (0)
 
 #define EM28XX_DVB_NUM_BUFS 5
-#define EM28XX_DVB_MAX_PACKETSIZE 564
 #define EM28XX_DVB_MAX_PACKETS 64
 
 struct em28xx_dvb {
@@ -142,14 +141,17 @@ static int start_streaming(struct em28xx_dvb *dvb)
 {
         int rc;
         struct em28xx *dev = dvb->adapter.priv;
+        int max_dvb_packet_size;
 
         usb_set_interface(dev->udev, 0, 1);
         rc = em28xx_set_mode(dev, EM28XX_DIGITAL_MODE);
         if (rc < 0)
                 return rc;
 
+        max_dvb_packet_size = em28xx_isoc_dvb_max_packetsize(dev);
+
         return em28xx_init_isoc(dev, EM28XX_DVB_MAX_PACKETS,
-                                EM28XX_DVB_NUM_BUFS, EM28XX_DVB_MAX_PACKETSIZE,
+                                EM28XX_DVB_NUM_BUFS, max_dvb_packet_size,
                                 dvb_isoc_copy);
 }
 
diff --git a/drivers/media/video/em28xx/em28xx-reg.h b/drivers/media/video/em28xx/em28xx-reg.h
index 24e39c56811e..a2676d63cfd0 100644
--- a/drivers/media/video/em28xx/em28xx-reg.h
+++ b/drivers/media/video/em28xx/em28xx-reg.h
@@ -27,6 +27,22 @@
 #define EM28XX_CHIPCFG_AC97                     0x10
 #define EM28XX_CHIPCFG_AUDIOMASK                0x30
 
+#define EM28XX_R01_CHIPCFG2     0x01
+
+/* em28xx Chip Configuration 2 0x01 */
+#define EM28XX_CHIPCFG2_TS_PRESENT              0x10
+#define EM28XX_CHIPCFG2_TS_REQ_INTERVAL_MASK    0x0c /* bits 3-2 */
+#define EM28XX_CHIPCFG2_TS_REQ_INTERVAL_1MF     0x00
+#define EM28XX_CHIPCFG2_TS_REQ_INTERVAL_2MF     0x04
+#define EM28XX_CHIPCFG2_TS_REQ_INTERVAL_4MF     0x08
+#define EM28XX_CHIPCFG2_TS_REQ_INTERVAL_8MF     0x0c
+#define EM28XX_CHIPCFG2_TS_PACKETSIZE_MASK      0x03 /* bits 0-1 */
+#define EM28XX_CHIPCFG2_TS_PACKETSIZE_188       0x00
+#define EM28XX_CHIPCFG2_TS_PACKETSIZE_376       0x01
+#define EM28XX_CHIPCFG2_TS_PACKETSIZE_564       0x02
+#define EM28XX_CHIPCFG2_TS_PACKETSIZE_752       0x03
+
+
         /* GPIO/GPO registers */
 #define EM2880_R04_GPO  0x04    /* em2880-em2883 only */
 #define EM28XX_R08_GPIO 0x08    /* em2820 or upper */
diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 16f4c23f179b..e801f783bdc3 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -616,6 +616,7 @@ int em28xx_init_isoc(struct em28xx *dev, int max_packets,
                      int num_bufs, int max_pkt_size,
                      int (*isoc_copy) (struct em28xx *dev, struct urb *urb));
 void em28xx_uninit_isoc(struct em28xx *dev);
+int em28xx_isoc_dvb_max_packetsize(struct em28xx *dev);
 int em28xx_set_mode(struct em28xx *dev, enum em28xx_mode set_mode);
 int em28xx_gpio_set(struct em28xx *dev, struct em28xx_reg_seq *gpio);
 void em28xx_wake_i2c(struct em28xx *dev);