The MXL5007T tuner will lock-up on some devices after an I2C
read transaction. This patch works around this issue by inhibiting such
operations and emulating a 0x00 response. The workaround is only applied to
USB devices known to exhibit this flaw.
Signed-off-by: Alessandro Radicati <alessan...@radicati.net>
---
drivers/media/usb/dvb-usb-v2/af9035.c | 21 +++++++++++++++++++++
drivers/media/usb/dvb-usb-v2/af9035.h | 1 +
2 files changed, 22 insertions(+)
diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c
b/drivers/media/usb/dvb-usb-v2/af9035.c
index 2638e32..06e300e 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -348,6 +348,9 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
ret = af9035_rd_regs(d, reg, &msg[1].buf[0],
msg[1].len);
+ } else if (state->no_read) {
+ memset(msg[1].buf, 0, msg[1].len);
+ ret = 0;
} else {
/* I2C write + read */
u8 buf[MAX_XFER_SIZE];
@@ -421,6 +424,9 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
if (msg[0].len > 40) {
/* TODO: correct limits > 40 */
ret = -EOPNOTSUPP;
+ } else if (state->no_read) {
+ memset(msg[0].buf, 0, msg[0].len);
+ ret = 0;
} else {
/* I2C read */
u8 buf[5];
@@ -962,6 +968,21 @@ skip_eeprom:
state->af9033_config[i].clock = clock_lut_af9035[tmp];
}
+ state->no_read = false;
+ /* Some MXL5007T devices cannot properly handle tuner I2C read ops. */
+ if (state->af9033_config[0].tuner == AF9033_TUNER_MXL5007T &&
+ le16_to_cpu(d->udev->descriptor.idVendor) == USB_VID_AVERMEDIA)
+
+ switch (le16_to_cpu(d->udev->descriptor.idProduct)) {
+ case USB_PID_AVERMEDIA_A867:
+ case USB_PID_AVERMEDIA_TWINSTAR:
+ dev_info(&d->udev->dev,
+ "%s: Device may have issues with I2C read
operations. Enabling fix.\n",
+ KBUILD_MODNAME);
+ state->no_read = true;
+ break;
+ }
+
return 0;
err:
diff --git a/drivers/media/usb/dvb-usb-v2/af9035.h
b/drivers/media/usb/dvb-usb-v2/af9035.h
index 89e629a..c91d1a3 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.h
+++ b/drivers/media/usb/dvb-usb-v2/af9035.h
@@ -62,6 +62,7 @@ struct state {
u8 chip_version;
u16 chip_type;
u8 dual_mode:1;
+ u8 no_read:1;
u16 eeprom_addr;
u8 af9033_i2c_addr[2];
struct af9033_config af9033_config[2];
--
2.7.4
--
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