android_kernel_motorola_sm6375/include
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Denis OSTERLAND-HEIM 7465f4f15f pps: fix poll support
[ Upstream commit 12c409aa1ec2592280a2ddcc66ff8f3c7f7bb171 ]

Because pps_cdev_poll() returns unconditionally EPOLLIN,
a user space program that calls select/poll get always an immediate data
ready-to-read response. As a result the intended use to wait until next
data becomes ready does not work.

User space snippet:

    struct pollfd pollfd = {
      .fd = open("/dev/pps0", O_RDONLY),
      .events = POLLIN|POLLERR,
      .revents = 0 };
    while(1) {
      poll(&pollfd, 1, 2000/*ms*/); // returns immediate, but should wait
      if(revents & EPOLLIN) { // always true
        struct pps_fdata fdata;
        memset(&fdata, 0, sizeof(memdata));
        ioctl(PPS_FETCH, &fdata); // currently fetches data at max speed
      }
    }

Lets remember the last fetch event counter and compare this value
in pps_cdev_poll() with most recent event counter
and return 0 if they are equal.

Signed-off-by: Denis OSTERLAND-HEIM <denis.osterland@diehl.com>
Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
Fixes: eae9d2ba0c ("LinuxPPS: core support")
Link: https://lore.kernel.org/all/f6bed779-6d59-4f0f-8a59-b6312bd83b4e@enneenne.com/
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/c3c50ad1eb19ef553eca8a57c17f4c006413ab70.camel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-28 16:21:18 +02:00
..
acpi ACPICA: Avoid sequence overread in call to strncmp() 2025-06-27 11:02:52 +01:00
asm-generic
clocksource
crypto
drm drm/sched: Increment job count before swapping tail spsc queue 2025-07-17 18:25:03 +02:00
dt-bindings
keys
kvm
linux pps: fix poll support 2025-08-28 16:21:18 +02:00
math-emu
media
misc
net netfilter: nf_tables: do not defer rule destruction via call_rcu 2025-06-04 14:32:36 +02:00
pcmcia
ras
rdma RDMA/core: Create and destroy counters in the ib_core 2025-07-17 18:24:59 +02:00
scsi
soc
sound ALSA: pcm: Fix race of buffer access at PCM OSS layer 2025-06-04 14:32:35 +02:00
target
trace erofs: remove unused trace event erofs_destroy_inode 2025-06-27 11:02:57 +01:00
uapi vsock/uapi: fix linux/vm_sockets.h userspace compilation errors 2025-07-17 18:24:53 +02:00
vdso
video
xen xen/mcelog: Add __nonstring annotations for unterminated strings 2025-05-02 07:39:09 +02:00