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authorAkihiro Tsukada <tskd2@yahoo.co.jp>2012-03-10 18:38:13 +0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-03-19 22:46:36 +0400
commit847e87659620890bfc80ce7bf682f2a5354543b2 (patch)
treeb9929128874639472b0892e58ab10eddc8db71e0 /drivers/media/dvb
parent2321acf2962514088c2230b6d54f7a56368576c5 (diff)
downloadlinux-847e87659620890bfc80ce7bf682f2a5354543b2.tar.xz
[media] dvb: earth-pt1: stop polling data when no one accesses the device
The driver started a kthread to poll the DMA buffers soon after probing, which relsuleted in 1000/sec sleeps and wakeups of the thread doing nothing useful until someone started feeding. This patch changes the creation and destruction of the kthread depending on the number of users. Signed-off-by: Akihiro Tsukada <tskd2@yahoo.co.jp> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/dvb')
-rw-r--r--drivers/media/dvb/pt1/pt1.c73
1 files changed, 50 insertions, 23 deletions
diff --git a/drivers/media/dvb/pt1/pt1.c b/drivers/media/dvb/pt1/pt1.c
index b81df5fafe26..463f7849c44c 100644
--- a/drivers/media/dvb/pt1/pt1.c
+++ b/drivers/media/dvb/pt1/pt1.c
@@ -77,6 +77,8 @@ struct pt1 {
struct pt1_adapter *adaps[PT1_NR_ADAPS];
struct pt1_table *tables;
struct task_struct *kthread;
+ int table_index;
+ int buf_index;
struct mutex lock;
int power;
@@ -303,30 +305,25 @@ static int pt1_filter(struct pt1 *pt1, struct pt1_buffer_page *page)
static int pt1_thread(void *data)
{
struct pt1 *pt1;
- int table_index;
- int buf_index;
struct pt1_buffer_page *page;
pt1 = data;
set_freezable();
- table_index = 0;
- buf_index = 0;
-
while (!kthread_should_stop()) {
try_to_freeze();
- page = pt1->tables[table_index].bufs[buf_index].page;
+ page = pt1->tables[pt1->table_index].bufs[pt1->buf_index].page;
if (!pt1_filter(pt1, page)) {
schedule_timeout_interruptible((HZ + 999) / 1000);
continue;
}
- if (++buf_index >= PT1_NR_BUFS) {
+ if (++pt1->buf_index >= PT1_NR_BUFS) {
pt1_increment_table_count(pt1);
- buf_index = 0;
- if (++table_index >= pt1_nr_tables)
- table_index = 0;
+ pt1->buf_index = 0;
+ if (++pt1->table_index >= pt1_nr_tables)
+ pt1->table_index = 0;
}
}
@@ -477,21 +474,60 @@ err:
return ret;
}
+static int pt1_start_polling(struct pt1 *pt1)
+{
+ int ret = 0;
+
+ mutex_lock(&pt1->lock);
+ if (!pt1->kthread) {
+ pt1->kthread = kthread_run(pt1_thread, pt1, "earth-pt1");
+ if (IS_ERR(pt1->kthread)) {
+ ret = PTR_ERR(pt1->kthread);
+ pt1->kthread = NULL;
+ }
+ }
+ mutex_unlock(&pt1->lock);
+ return ret;
+}
+
static int pt1_start_feed(struct dvb_demux_feed *feed)
{
struct pt1_adapter *adap;
adap = container_of(feed->demux, struct pt1_adapter, demux);
- if (!adap->users++)
+ if (!adap->users++) {
+ int ret;
+
+ ret = pt1_start_polling(adap->pt1);
+ if (ret)
+ return ret;
pt1_set_stream(adap->pt1, adap->index, 1);
+ }
return 0;
}
+static void pt1_stop_polling(struct pt1 *pt1)
+{
+ int i, count;
+
+ mutex_lock(&pt1->lock);
+ for (i = 0, count = 0; i < PT1_NR_ADAPS; i++)
+ count += pt1->adaps[i]->users;
+
+ if (count == 0 && pt1->kthread) {
+ kthread_stop(pt1->kthread);
+ pt1->kthread = NULL;
+ }
+ mutex_unlock(&pt1->lock);
+}
+
static int pt1_stop_feed(struct dvb_demux_feed *feed)
{
struct pt1_adapter *adap;
adap = container_of(feed->demux, struct pt1_adapter, demux);
- if (!--adap->users)
+ if (!--adap->users) {
pt1_set_stream(adap->pt1, adap->index, 0);
+ pt1_stop_polling(adap->pt1);
+ }
return 0;
}
@@ -1020,7 +1056,8 @@ static void __devexit pt1_remove(struct pci_dev *pdev)
pt1 = pci_get_drvdata(pdev);
regs = pt1->regs;
- kthread_stop(pt1->kthread);
+ if (pt1->kthread)
+ kthread_stop(pt1->kthread);
pt1_cleanup_tables(pt1);
pt1_cleanup_frontends(pt1);
pt1_disable_ram(pt1);
@@ -1043,7 +1080,6 @@ pt1_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
void __iomem *regs;
struct pt1 *pt1;
struct i2c_adapter *i2c_adap;
- struct task_struct *kthread;
ret = pci_enable_device(pdev);
if (ret < 0)
@@ -1139,17 +1175,8 @@ pt1_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
if (ret < 0)
goto err_pt1_cleanup_frontends;
- kthread = kthread_run(pt1_thread, pt1, "pt1");
- if (IS_ERR(kthread)) {
- ret = PTR_ERR(kthread);
- goto err_pt1_cleanup_tables;
- }
-
- pt1->kthread = kthread;
return 0;
-err_pt1_cleanup_tables:
- pt1_cleanup_tables(pt1);
err_pt1_cleanup_frontends:
pt1_cleanup_frontends(pt1);
err_pt1_disable_ram: