Em Wed, 5 Oct 2016 09:50:42 +0200 (CEST)
Jiri Kosina <jikos@xxxxxxxxxx> escreveu:
> On Wed, 5 Oct 2016, Patrick Boettcher wrote:
>
> > > > Thanks for the quick response.
> > > > Drivers are:
> > > > dvb_core, dvb_usb, dbv_usb_cynergyT2
> > >
> > > This dbv_usb_cynergyT2 is not from Linus' tree, is it? I don't seem
> > > to be able to find it, and the only google hit I am getting is your
> > > very mail to LKML :)
> >
> > It's a typo, it should say dvb_usb_cinergyT2.
>
> Ah, thanks. Same issues there in
>
> cinergyt2_frontend_attach()
> cinergyt2_rc_query()
>
> I think this would require more in-depth review of all the media drivers
> and having all this fixed for 4.9. It should be pretty straightforward;
> all the instances I've seen so far should be just straightforward
> conversion to kmalloc() + kfree(), as the buffer is not being embedded in
> any structure etc.
What we're doing on most cases is to put a buffer (usually with 80
chars for USB drivers) inside the "state" struct (on DVB drivers),
in order to avoid doing kmalloc/kfree all the times. One such patch is
changeset c4a98793a63c4.
I'm enclosing a non-tested patch fixing it for the cinergyT2-core.c
driver.
Thanks,
Mauro
[PATCH] cinergyT2-core: don't do DMA on stack
The USB control messages require DMA to work. We cannot pass
a stack-allocated buffer, as it is not warranted that the
stack would be into a DMA enabled area.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
diff --git a/drivers/media/usb/dvb-usb/cinergyT2-core.c b/drivers/media/usb/dvb-usb/cinergyT2-core.c
index 9fd1527494eb..2787acc74fcc 100644
--- a/drivers/media/usb/dvb-usb/cinergyT2-core.c
+++ b/drivers/media/usb/dvb-usb/cinergyT2-core.c
@@ -41,6 +41,7 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
struct cinergyt2_state {
u8 rc_counter;
+ unsigned char data[64];
};
/* We are missing a release hook with usb_device data */
@@ -50,29 +51,34 @@ static struct dvb_usb_device_properties cinergyt2_properties;
static int cinergyt2_streaming_ctrl(struct dvb_usb_adapter *adap, int enable)
{
- char buf[] = { CINERGYT2_EP1_CONTROL_STREAM_TRANSFER, enable ? 1 : 0 };
- char result[64];
- return dvb_usb_generic_rw(adap->dev, buf, sizeof(buf), result,
- sizeof(result), 0);
+ struct dvb_usb_device *d = adap->dev;
+ struct cinergyt2_state *st = d->priv;
+
+ st->data[0] = CINERGYT2_EP1_CONTROL_STREAM_TRANSFER;
+ st->data[1] = enable ? 1 : 0;
+
+ return dvb_usb_generic_rw(d, st->data, 2, st->data, 64, 0);
}
static int cinergyt2_power_ctrl(struct dvb_usb_device *d, int enable)
{
- char buf[] = { CINERGYT2_EP1_SLEEP_MODE, enable ? 0 : 1 };
- char state[3];
- return dvb_usb_generic_rw(d, buf, sizeof(buf), state, sizeof(state), 0);
+ struct cinergyt2_state *st = d->priv;
+
+ st->data[0] = CINERGYT2_EP1_SLEEP_MODE;
+ st->data[1] = enable ? 1 : 0;
+
+ return dvb_usb_generic_rw(d, st->data, 2, st->data, 3, 0);
}
static int cinergyt2_frontend_attach(struct dvb_usb_adapter *adap)
{
- char query[] = { CINERGYT2_EP1_GET_FIRMWARE_VERSION };
- char state[3];
+ struct dvb_usb_device *d = adap->dev;
+ struct cinergyt2_state *st = d->priv;
int ret;
adap->fe_adap[0].fe = cinergyt2_fe_attach(adap->dev);
- ret = dvb_usb_generic_rw(adap->dev, query, sizeof(query), state,
- sizeof(state), 0);
+ ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 3, 0);
if (ret < 0) {
deb_rc("cinergyt2_power_ctrl() Failed to retrieve sleep "
"state info\n");
@@ -141,13 +147,14 @@ static int repeatable_keys[] = {
static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
{
struct cinergyt2_state *st = d->priv;
- u8 key[5] = {0, 0, 0, 0, 0}, cmd = CINERGYT2_EP1_GET_RC_EVENTS;
int i;
*state = REMOTE_NO_KEY_PRESSED;
- dvb_usb_generic_rw(d, &cmd, 1, key, sizeof(key), 0);
- if (key[4] == 0xff) {
+ st->data[0] = CINERGYT2_EP1_SLEEP_MODE;
+
+ dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+ if (st->data[4] == 0xff) {
/* key repeat */
st->rc_counter++;
if (st->rc_counter > RC_REPEAT_DELAY) {
@@ -166,13 +173,13 @@ static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
}
/* hack to pass checksum on the custom field */
- key[2] = ~key[1];
- dvb_usb_nec_rc_key_to_event(d, key, event, state);
- if (key[0] != 0) {
+ st->data[2] = ~st->data[1];
+ dvb_usb_nec_rc_key_to_event(d, st->data, event, state);
+ if (st->data[0] != 0) {
if (*event != d->last_event)
st->rc_counter = 0;
- deb_rc("key: %*ph\n", 5, key);
+ deb_rc("key: %*ph\n", 5, st->data);
}
return 0;
}
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