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Groups > linux.kernel > #1496805
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2] cinergyT2-core: don't do DMA on stack |
| Date | 2016-10-06 20:40 +0200 |
| Message-ID | <splKi-4z5-23@gated-at.bofh.it> (permalink) |
| References | <soZA5-5oJ-19@gated-at.bofh.it> <spkEy-3Bo-5@gated-at.bofh.it> |
| Organization | Samsung |
Em Thu, 6 Oct 2016 10:27:56 -0700
Andy Lutomirski <luto@amacapital.net> escreveu:
> On Wed, Oct 5, 2016 at 11:58 AM, Mauro Carvalho Chehab
> <mchehab@s-opensource.com> wrote:
> > Sorry, forgot to C/C people that are at the "Re: Problem with VMAP_STACK=y"
> > thread.
> >
> > Forwarded message:
> >
> > Date: Wed, 5 Oct 2016 15:54:18 -0300
> > From: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> > To: Linux Doc Mailing List <linux-doc@vger.kernel.org>
> > Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>, Mauro Carvalho Chehab <mchehab@infradead.org>, Mauro Carvalho Chehab <mchehab@kernel.org>
> > Subject: [PATCH v2] 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@s-opensource.com>
> > ---
> >
> > Added the fixups made by Johannes Stezenbach
> >
> > drivers/media/usb/dvb-usb/cinergyT2-core.c | 45 ++++++++++++++++++------------
> > 1 file changed, 27 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/media/usb/dvb-usb/cinergyT2-core.c b/drivers/media/usb/dvb-usb/cinergyT2-core.c
> > index 9fd1527494eb..8267e3777af6 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 +51,36 @@ 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)
> > {
>
> This...
>
> > - 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;
>
> ...does not match this:
>
> > + st->data[1] = enable ? 1 : 0;
>
> --Andy
Gah! Yes. This is what happens when coding using cut-and-paste ;)
Jörg,
Please test it with the condition reversed with the enclosed patch.
if this doesn't work, you can enable dvb-usb debug at runtime,
by loading it with debug parameter:
parm: debug:set debugging level (1=info,xfer=2,pll=4,ts=8,err=16,rc=32,fw=64,mem=128,uxfer=256 (or-able)). (debugging is not enabled) (int)
debug=2 should show the control messages sent to the device on dmesg.
Regards,
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@s-opensource.com>
diff --git a/drivers/media/usb/dvb-usb/cinergyT2-core.c b/drivers/media/usb/dvb-usb/cinergyT2-core.c
index 9fd1527494eb..91640c927776 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 +51,36 @@ 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 ? 0 : 1;
+
+ 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);
+ st->data[0] = CINERGYT2_EP1_GET_FIRMWARE_VERSION;
+
+ 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 +149,14 @@ 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_GET_RC_EVENTS;
+
+ 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 +175,13 @@ 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;
}
Thanks,
Mauro
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Fw: [PATCH v2] cinergyT2-core: don't do DMA on stack Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2016-10-05 21:00 +0200
Re: Fw: [PATCH v2] cinergyT2-core: don't do DMA on stack Andy Lutomirski <luto@amacapital.net> - 2016-10-06 19:30 +0200
Re: [PATCH v2] cinergyT2-core: don't do DMA on stack Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2016-10-06 20:40 +0200
Re: [PATCH v2] cinergyT2-core: don't do DMA on stack Jörg Otte <jrg.otte@gmail.com> - 2016-10-07 16:00 +0200
Re: [PATCH v2] cinergyT2-core: don't do DMA on stack Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2016-10-07 19:40 +0200
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