On 22/09/2023 13:22, Laurent Pinchart wrote:
On Fri, Sep 22, 2023 at 01:16:21PM +0300, Tomi Valkeinen wrote:
On 22/09/2023 13:09, Sakari Ailus wrote:
On Fri, Sep 22, 2023 at 12:53:20PM +0300, Laurent Pinchart wrote:
On Fri, Sep 22, 2023 at 09:41:01AM +0000, Sakari Ailus wrote:
On Tue, Sep 19, 2023 at 06:21:23PM +0300, Laurent Pinchart wrote:
On Tue, Sep 19, 2023 at 02:49:29PM +0000, Sakari Ailus wrote:
On Tue, Sep 19, 2023 at 04:32:48PM +0300, Laurent Pinchart wrote:
On Tue, Sep 19, 2023 at 03:17:27PM +0300, Sakari Ailus wrote:
Print debug level information on returned frame descriptors.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-subdev.c | 32 ++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 7b087be3ff4f..504ca625b2bd 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/overflow.h>
#include <linux/slab.h>
+#include <linux/string.h>
#include <linux/types.h>
#include <linux/version.h>
#include <linux/videodev2.h>
@@ -309,9 +310,38 @@ static int call_set_selection(struct v4l2_subdev *sd,
static int call_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
struct v4l2_mbus_frame_desc *fd)
{
+ unsigned int i;
+ int ret;
+
memset(fd, 0, sizeof(*fd));
- return sd->ops->pad->get_frame_desc(sd, pad, fd);
+ ret = sd->ops->pad->get_frame_desc(sd, pad, fd);
+ if (ret)
+ return ret;
+
+ dev_dbg(sd->dev, "Frame descriptor on pad %u, type %s\n", pad,
+ fd->type == V4L2_MBUS_FRAME_DESC_TYPE_PARALLEL ? "parallel" :
+ fd->type == V4L2_MBUS_FRAME_DESC_TYPE_CSI2 ? "CSI-2" :
+ "unknown");
+
+ for (i = 0; i < fd->num_entries; i++) {
+ struct v4l2_mbus_frame_desc_entry *entry = &fd->entry[i];
+ char buf[20] = "";
Should this be sized for the worst case ? The vc and dt should not be
large, but a buffer overflow on the stack in debug code if a subdev
returns an incorrect value would be bad.
17 should be enough but it's not useful to use a size not divisible by 4 in
practice here.
18 with the terminating 0. But indeed, it's large enough as vc and dt
I can count only 17 --- there's no newline.
I guess it's most probably either of these then. X-)
are u8. I'm just a bit worried we're opening the door to hard to debug
problems if we later change the vc and dt types.
I can add a WARN_ON() to cover this.
+
+ if (fd->type == V4L2_MBUS_FRAME_DESC_TYPE_CSI2)
+ snprintf(buf, sizeof(buf), ", vc %u, dt 0x%2.2x",
0x%02x would be one character shorter ;-) Same below.
It would be, but I prefer the above notation as it's more generic.
Out of curiosity, how so ?
It works with data that would span more than 9 characters when printed.
And 0x%02x doesn't ?
Ah, it should indeed work, 0 is actually a flag here and part of the field
width or precision. I can use that in v4.
Or %#04x, even shorter!
That's different though.
printf("0x%2.2x\n", 0); -> 0x00
printf("0x%2.2x\n", 1); -> 0x01
printf("0x%2.2x\n", 42); -> 0x2a
printf("0x%02x\n", 0); -> 0x00
printf("0x%02x\n", 1); -> 0x01
printf("0x%02x\n", 42); -> 0x2a
printf("%#2.2x\n", 0); -> 00
printf("%#2.2x\n", 1); -> 0x01
printf("%#2.2x\n", 42); -> 0x2a
printf("%#02x\n", 0); -> 00
printf("%#02x\n", 1); -> 0x1
printf("%#02x\n", 42); -> 0x2a
The length should be 4 there, not 2. But even after fixing that, the 0
case is printed wrong. Interesting, I haven't noticed that before. I
wonder why it behaves that way...
0000
0x01
0x2a
Tomi
