Re: [PATCH] media: nxp: imx8-isi: add m2m usage_count check in streamoff
From: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Date: 2024-09-23 17:50:29
Also in:
imx, linux-media, lkml
Hi Laurentiu On Fri, Sep 20, 2024 at 05:27:15PM GMT, Laurentiu Palcu wrote:
Currently, if streamon/streamoff calls are imbalanced we can end up with a negative ISI m2m usage_count. When that happens, the next streamon call will not enable the ISI m2m channel. So, instead of throwing a warning in streamoff when usage_count drops below 0, just make sure we don't get there.
Isn't the whole purpose of the WARN() to highlight something's wrong with userspace ? I think it's expected to have the same number of streamon and streamoff calls, do you have any idea why it might not be happening ? Thanks j
quoted hunk ↗ jump to hunk
Fixes: cf21f328fcafac ("media: nxp: Add i.MX8 ISI driver") Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com> --- drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c index 9745d6219a166..b71195a3ba256 100644 --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c@@ -575,6 +575,9 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, mutex_lock(&m2m->lock); + if (m2m->usage_count == 0) + goto unlock; + /* * If the last context is this one, reset it to make sure the device * will be reconfigured when streaming is restarted.@@ -594,8 +597,7 @@ static int mxc_isi_m2m_streamoff(struct file *file, void *fh, mxc_isi_channel_release(m2m->pipe); } - WARN_ON(m2m->usage_count < 0); - +unlock: mutex_unlock(&m2m->lock); return 0; --2.34.1