Re: [PATCH v2] cinergyT2-core: don't do DMA on stack

[JÃrg Otte]

2016-10-06 20:29 GMT+02:00 Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>:
> Em Thu, 6 Oct 2016 10:27:56 -0700
> Andy Lutomirski <luto@xxxxxxxxxxxxxx> escreveu:
>
>> On Wed, Oct 5, 2016 at 11:58 AM, Mauro Carvalho Chehab
>> <mchehab@xxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxx>
>> > To: Linux Doc Mailing List <linux-doc@xxxxxxxxxxxxxxx>
>> > Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>, Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx>, Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
>> > 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@xxxxxxxxxxxxxxxx>
>> > ---
>> >
>> > 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 ;)
>
> JÃrg,
>
> 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@xxxxxxxxxxxxxxxx>
>
> 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

Patch works for me!
Thanks, JÃrg