iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

media: qcom: camss: Fix VFE-17x vfe_disable_output()

Browse Source 
There are two problems with the current vfe_disable_output() routine.

Firstly we rightly use a spinlock to protect output->gen2.active_num
everywhere except for in the IDLE timeout path of vfe_disable_output().
Even if that is not racy "in practice" somehow it is by happenstance not
by design.

Secondly we do not get consistent behaviour from this routine. On
sc8280xp 50% of the time I get "VFE idle timeout - resetting". In this
case the subsequent capture will succeed. The other 50% of the time, we
don't hit the idle timeout, never do the VFE reset and subsequent
captures stall indefinitely.

Rewrite the vfe_disable_output() routine to

- Quiesce write masters with vfe_wm_stop()
- Set active_num = 0

remembering to hold the spinlock when we do so followed by

- Reset the VFE

Testing on sc8280xp and sdm845 shows this to be a valid fix.

Fixes: 7319cdf189bb ("media: camss: Add support for VFE hardware version Titan 170")
Cc: stable@vger.kernel.org
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
This commit is contained in:
Bryan O'Donoghue 2023-08-30 16:16:10 +01:00 committed by Hans Verkuil
parent 26bda3da00
commit 3143ad282f
1 changed files with 3 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/media/platform/qcom/camss/camss-vfe-170.c
View File

@ -7,7 +7,6 @@
* Copyright (C) 2020-2021 Linaro Ltd.
*/
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
@ -494,35 +493,20 @@ static int vfe_enable_output(struct vfe_line *line)
return 0;
}
static int vfe_disable_output(struct vfe_line *line)
static void vfe_disable_output(struct vfe_line *line)
{
struct vfe_device *vfe = to_vfe(line);
struct vfe_output *output = &line->output;
unsigned long flags;
unsigned int i;
bool done;
int timeout = 0;
do {
spin_lock_irqsave(&vfe->output_lock, flags);
done = !output->gen2.active_num;
spin_unlock_irqrestore(&vfe->output_lock, flags);
usleep_range(10000, 20000);
if (timeout++ == 100) {
dev_err(vfe->camss->dev, "VFE idle timeout - resetting\n");
vfe_reset(vfe);
output->gen2.active_num = 0;
return 0;
}
} while (!done);
spin_lock_irqsave(&vfe->output_lock, flags);
for (i = 0; i < output->wm_num; i++)
vfe_wm_stop(vfe, output->wm_idx[i]);
output->gen2.active_num = 0;
spin_unlock_irqrestore(&vfe->output_lock, flags);
return 0;
vfe_reset(vfe);
}
/*