Messages in this thread | | | From | <> | Subject | Re: [PATCH 03/16] iio: adc: at91-sama5d2_adc: exit from write_raw() when buffers are enabled | Date | Tue, 14 Jun 2022 08:19:44 +0000 |
| |
On 11.06.2022 20:33, Jonathan Cameron wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > On Thu, 9 Jun 2022 11:32:00 +0300 > Claudiu Beznea <claudiu.beznea@microchip.com> wrote: > >> When buffers are enabled conversion may start asynchronously thus >> allowing changes on actual hardware could lead to bad behavior. Thus >> do not allow changing oversampling ratio and sample frequency when >> buffers are enabled. > > Less than desirable behavior perhaps, but broken? I don't see this > as a fix from what you have mentioned - though I'm not against it. > (just drop the fixes tag) > It is an ABI change, but unlikely to be one any sane code hits. > >> >> Fixes: 5e1a1da0f8c9 ("iio: adc: at91-sama5d2_adc: add hw trigger and buffer support") >> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> >> --- >> drivers/iio/adc/at91-sama5d2_adc.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c >> index a672a520cdc0..b76328da0cb2 100644 >> --- a/drivers/iio/adc/at91-sama5d2_adc.c >> +++ b/drivers/iio/adc/at91-sama5d2_adc.c >> @@ -1644,6 +1644,9 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev, >> { >> struct at91_adc_state *st = iio_priv(indio_dev); >> >> + if (iio_buffer_enabled(indio_dev)) >> + return -EBUSY; > > This is racy as nothing stops buffers being enabled after this point. > Use the iio_device_claim_direct_mode() and release for this as they > protect against the race.
OK, thanks!
> > >> + >> switch (mask) { >> case IIO_CHAN_INFO_OVERSAMPLING_RATIO: >> if ((val != AT91_OSR_1SAMPLES) && (val != AT91_OSR_4SAMPLES) && >
| |