Messages in this thread | | | Date | Sun, 21 Jun 2020 20:07:20 -0400 | From | Sasha Levin <> | Subject | Re: [PATCH AUTOSEL 4.4 23/60] iio: buffer: Don't allow buffers without any channels enabled to be activated |
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On Fri, Jun 19, 2020 at 05:27:33PM +0100, Jonathan Cameron wrote: >On Wed, 17 Jun 2020 21:29:27 -0400 >Sasha Levin <sashal@kernel.org> wrote: > >> From: Lars-Peter Clausen <lars@metafoo.de> >> >> [ Upstream commit b7329249ea5b08b2a1c2c3f24a2f4c495c4f14b8 ] >> >> Before activating a buffer make sure that at least one channel is enabled. >> Activating a buffer with 0 channels enabled doesn't make too much sense and >> disallowing this case makes sure that individual driver don't have to add >> special case code to handle it. >> >> Currently, without this patch enabling a buffer is possible and no error is >> produced. With this patch -EINVAL is returned. >> >> An example of execution with this patch and some instrumented print-code: >> root@analog:~# cd /sys/bus/iio/devices/iio\:device3/buffer >> root@analog:/sys/bus/iio/devices/iio:device3/buffer# echo 1 > enable >> 0: iio_verify_update 748 indio_dev->masklength 2 *insert_buffer->scan_mask 00000000 >> 1: iio_verify_update 753 >> 2:__iio_update_buffers 1115 ret -22 >> 3: iio_buffer_store_enable 1241 ret -22 >> -bash: echo: write error: Invalid argument >> 1, 2 & 3 are exit-error paths. 0 the first print in iio_verify_update() >> rergardless of error path. >> >> Without this patch (and same instrumented print-code): >> root@analog:~# cd /sys/bus/iio/devices/iio\:device3/buffer >> root@analog:/sys/bus/iio/devices/iio:device3/buffer# echo 1 > enable >> 0: iio_verify_update 748 indio_dev->masklength 2 *insert_buffer->scan_mask 00000000 >> root@analog:/sys/bus/iio/devices/iio:device3/buffer# >> Buffer is enabled with no error. >> >> Note from Jonathan: Probably not suitable for automatic application to stable. >> This has been there from the very start. It tidies up an odd corner >> case but won't effect any 'real' users. >> > >As noted. I don't think it matters if we do apply this to stable. >It closes an interface oddity rather than an actual known bug.
I'll drop it, thanks!
-- Thanks, Sasha
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