Dne 26.4.2018 v 14:44 Arnd Bergmann napsal(a):
I've tried the suggestion from Jaroslaw, doing a minimal change to the UAPI headers to keep the existing binary interface. As he predicted, this is a much simpler set of kernel changes, but we will pay for that with added complexity in alsa-lib.
The first two patches in this series are taken from Baolin's patch set, with a small bugfix folded in to avoid a compile-time regression.
The other two patches are to redefine the UAPI and to deprecate the support for CLOCK_REALTIME time stamps, which we can no longer allow with user space that we expect to survive beyond 2038.
Overall, I'd still be happier with Baolin's approach since it allows us to keep compatiblity with CLOCK_REALTIME users and requires fewer changes in user space, but this would work as well.
Hi Arnd,
Thanks for your work. I proposed a bit different implementation. Example:
struct snd_example { struct snd_native_timespec tstamp; .... u64 tstamp_sec64; /* use the reserved[] array for this */ };
So tstamp contains the current 32-bit tv_sec/tv_nsec and the full 64-bit value is in tstamp_sec64. In this way, we can transfer any type of the timespec64 values and it's backward compatible to retain the binary compatibility. The protocol versions should be increased to let the userspace know about the new 64-bit fields.
The timer read protocol must be updated, because the stream will change, so I am fine to add new ioctl (like originally proposed).
The alsa-lib defines timespec only if posix defines are not set so glibc's time.h does not define the timespec structure - it may be improved.
Jaroslav
Arnd
Cc: Jaroslav Kysela perex@perex.cz Cc: tiwai@suse.com Cc: lgirdwood@gmail.com Cc: broonie@kernel.org Cc: o-takashi@sakamocchi.jp Cc: y2038@lists.linaro.org Cc: alsa-devel@alsa-project.org Cc: linux-kernel@vger.kernel.org Cc: Baolin Wang baolin.wang@linaro.org
Arnd Bergmann (2): ALSA: replace timespec types in uapi headers ALSA: Deprecate CLOCK_REALTIME timestamps
Baolin Wang (2): ALSA: Replace timespec with timespec64 ALSA: Avoid using timespec for struct snd_ctl_elem_value
include/sound/asound.h | 8 +++++ include/sound/pcm.h | 22 +++++++----- include/sound/timer.h | 4 +-- include/uapi/sound/asound.h | 53 +++++++++++++++++++++-------- sound/core/Kconfig | 11 ++++++ sound/core/compat.h | 11 ++++++ sound/core/pcm.c | 3 ++ sound/core/pcm_compat.c | 70 ++++++++++++++++++++++----------------- sound/core/pcm_lib.c | 36 ++++++++++++-------- sound/core/pcm_native.c | 25 ++++++++++---- sound/core/rawmidi_compat.c | 12 +++---- sound/core/timer.c | 28 ++++++++-------- sound/core/timer_compat.c | 4 ++- sound/pci/hda/hda_controller.c | 14 +++++--- sound/soc/intel/skylake/skl-pcm.c | 4 +-- 15 files changed, 203 insertions(+), 102 deletions(-) create mode 100644 sound/core/compat.h