Dear All
Do you know how to change
from [PATCH] [PATCH] media: dvb_ca_en50221: Add a returing EBUSY logic in...
to [PATCH] media: dvb_ca_en50221: Add a returing EBUSY logic in... ?
2023년 12월 31일 (일) 오후 10:17, <yongsuyoo0215@xxxxxxxxx>님이 작성:
>
> From: Yongsu yoo <yongsuyoo0215@xxxxxxxxx>
>
> Signed-off-by:Yongsu Yoo <yongsuyoo0215@xxxxxxxxx>
>
> In source/drivers/media/dvb-core/dvb_ca_en50221.c, if the CA_RESET ioctl
> is called, in a normal case, the state of the thread of the
> dvb_ca_en50221_thread_state_machine will transit like below order.
> DVB_CA_SLOTSTATE_NONE -> DVB_CA_SLOTSTATE_UNINITIALISED ->
> DVB_CA_SLOTSTATE_WAITREADY -> DVB_CA_SLOTSTATE_VALIDATE ->
> DVB_CA_SLOTSTATE_WAITFR -> DVB_CA_SLOTSTATE_LINKINIT ->
> DVB_CA_SLOTSTATE_RUNNING
> But in some problem cases, the state will become DVB_CA_SLOTSTATE_INVALID.
> Among the above mentioned states, the DVB_CA_SLOTSTATE_NONE and
> the DVB_CA_SLOTSTATE_INVALID are "already stablized" states,
> whereas other states are "transiting" states.
> The "already stablized" states mean no matter how long time we wait,
> the state will not be changed.
> The "transiting" states mean the states whose final state is not yet
> determined. The state keeps to be changed. Only after some time passes,
> we get to know whether the final state will be DVB_CA_SLOTSTATE_RUNNING
> or DVB_CA_SLOTSTATE_INVALID.
> During the "transiting" states, we do not yet know whether the
> CA_RESET operation, which triggered the "transiting" states, will
> succeed or fail. For this reason, during the "transiting" states, if
> another CA_RESET ioctl is called and if this new CA_RESET ioctl
> operation begins again, it will be meaningless and waste time.
> For preventing this problem from happening, we make CA_RESET ioctl do
> nothing and only return EBUSY if the ioctl is called during the
> "transiting" states.
> ---
> drivers/media/dvb-core/dvb_ca_en50221.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb-core/dvb_ca_en50221.c
> index baf64540dc00..2e8aec354b7c 100644
> --- a/drivers/media/dvb-core/dvb_ca_en50221.c
> +++ b/drivers/media/dvb-core/dvb_ca_en50221.c
> @@ -1362,13 +1362,19 @@ static int dvb_ca_en50221_io_do_ioctl(struct file *file,
> struct dvb_ca_slot *sl = &ca->slot_info[slot];
>
> mutex_lock(&sl->slot_lock);
> - if (sl->slot_state != DVB_CA_SLOTSTATE_NONE) {
> + if ((sl->slot_state == DVB_CA_SLOTSTATE_RUNNING) ||
> + (sl->slot_state == DVB_CA_SLOTSTATE_INVALID)) {
> dvb_ca_en50221_slot_shutdown(ca, slot);
> if (ca->flags & DVB_CA_EN50221_FLAG_IRQ_CAMCHANGE)
> dvb_ca_en50221_camchange_irq(ca->pub,
> slot,
> DVB_CA_EN50221_CAMCHANGE_INSERTED);
> }
> + else {
> + if (sl->slot_state != DVB_CA_SLOTSTATE_NONE) {
> + err = -EBUSY;
> + }
> + }
> mutex_unlock(&sl->slot_lock);
> }
> ca->next_read_slot = 0;
> --
> 2.17.1
>
