Messages in this thread Patch in this message | | | From | Nicholas Mc Guire <> | Subject | [PATCH 1/3] media: smiapp: core: add range to usleep_range | Date | Sun, 7 Apr 2019 04:16:02 +0200 |
| |
Allow the hrtimer subsystem to coalesce delay timers of lower accuracy by providing a suitable range
Signed-off-by: Nicholas Mc Guire <hofrat@opentech.at> ---
Problem located by an experimental coccinelle script
hrtimers in atomic context have limited accuracy due to possible context-switching and interruption so the accuracy is limited anyway. Giving the hrtimer subsystem a reasonable range for merging hrtimers helps to reduce the load on the hrtimer subsystem. As this delays do not seem to mandate high accuracy the range of a factor two seems acceptable.
Patch was compile tested with: x86_64_defconfig + MEDIA_SUPPORT=m, MEDIA_CAMERA_SUPPORT=y, MEDIA_CONTROLLER=y, VIDEO_V4L2_SUBDEV_API=y, VIDEO_SMIAPP=m (with a number of sparse warnings on sizeof() usage)
Patch is against 5.1-rc3 (localversion-next is next-20190405)
drivers/media/i2c/smiapp/smiapp-core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/media/i2c/smiapp/smiapp-core.c b/drivers/media/i2c/smiapp/smiapp-core.c index 58a45c3..c0c29ec 100644 --- a/drivers/media/i2c/smiapp/smiapp-core.c +++ b/drivers/media/i2c/smiapp/smiapp-core.c @@ -1222,19 +1222,19 @@ static int smiapp_power_on(struct device *dev) dev_err(&client->dev, "failed to enable vana regulator\n"); return rval; } - usleep_range(1000, 1000); + usleep_range(1000, 2000); rval = clk_prepare_enable(sensor->ext_clk); if (rval < 0) { dev_dbg(&client->dev, "failed to enable xclk\n"); goto out_xclk_fail; } - usleep_range(1000, 1000); + usleep_range(1000, 2000); gpiod_set_value(sensor->xshutdown, 1); sleep = SMIAPP_RESET_DELAY(sensor->hwcfg->ext_clk); - usleep_range(sleep, sleep); + usleep_range(sleep, sleep*2); mutex_lock(&sensor->mutex); @@ -1381,7 +1381,7 @@ static int smiapp_power_off(struct device *dev) gpiod_set_value(sensor->xshutdown, 0); clk_disable_unprepare(sensor->ext_clk); - usleep_range(5000, 5000); + usleep_range(5000, 10000); regulator_disable(sensor->vana); sensor->streaming = false; -- 2.1.4
| |