Hi Cosmin, Laurent, On Wed, Nov 27, 2024 at 09:20:33AM +0200, Laurent Pinchart wrote: > On Mon, Nov 25, 2024 at 10:34:40PM +0200, Cosmin Tanislav wrote: > > On 11/23/24 11:32 PM, Laurent Pinchart wrote: > > > On Fri, Nov 22, 2024 at 05:33:39PM +0200, Cosmin Tanislav wrote: > > >> The error values end up being returned to userspace, it makes sense to > > >> have some useful information printed when debugging them, even if the > > >> reason for the errors are bad configs or internal driver issues. > > >> > > >> Replace dev_dbg() with dev_err() for errors. > > > > > > We use dev_dbg() on purpose for all errors that can be triggered > > > directly by applications. This includes in particular all pipeline > > > validation errors. > > > > > > The error paths in this specific patch shouldn't be in that category, as > > > all the validation should have been performed before starting subdevs > > > (assuming all drivers are correctly implemented, which is of course not > > > a given, but those issues should be fixed). I think we could therefore > > > switch to dev_err() here. However, I'm wondering what kind of issues > > > triggered this patch. What errors did you run into that would have > > > benefited from being reported more loudly, and were they caused by > > > driver bugs or userspace misconfiguring the device ? > > > > I've had this patch in my GMSL2 tree for some time now, I believe indeed > > the reasons why I've hit these error cases were the drivers being > > slightly broken, but I still think it is worthwhile to show an error > > message, to aid with debugging. Adding the entity name to the messages > > makes it even more clear where exactly the code is breaking. > > > > I can split it up into separate patches for dev_dbg() -> dev_err() and > > adding the entity name to the print statements for V2. > > I'm OK either way. If other people prefer keeping dev_dbg() then > splitting the patch in two would make sense. dev_dbg() seems the correct function here: these are user-triggerable errors that aren't related to hardware conditions. > > > >> Also, when using complex pipelines with multiple bridges between the > > >> video device and multiple source sub devices, printing just the video > > >> device name for each error does not provide enough context as to which > > >> operation failed. > > >> > > >> Add sub device entity name to the messages where possible to clarify the > > >> source of the errors. > > > > > > This can be considered as a standalone patch. > > > > > >> Signed-off-by: Cosmin Tanislav <demonsingur@xxxxxxxxx> > > >> --- > > >> drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++---------- > > >> 1 file changed, 12 insertions(+), 10 deletions(-) > > >> > > >> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c > > >> index 4f0eecd7fd66f..d51b4594d11c5 100644 > > >> --- a/drivers/media/v4l2-core/v4l2-subdev.c > > >> +++ b/drivers/media/v4l2-core/v4l2-subdev.c > > >> @@ -2303,20 +2303,21 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad, > > >> &found_streams, &enabled_streams); > > >> > > >> if (found_streams != streams_mask) { > > >> - dev_dbg(dev, "streams 0x%llx not found on %s:%u\n", > > >> + dev_err(dev, "streams 0x%llx not found on %s:%u\n", > > >> streams_mask & ~found_streams, sd->entity.name, pad); > > >> ret = -EINVAL; > > >> goto done; > > >> } > > >> > > >> if (enabled_streams) { > > >> - dev_dbg(dev, "streams 0x%llx already enabled on %s:%u\n", > > >> + dev_err(dev, "streams 0x%llx already enabled on %s:%u\n", > > >> enabled_streams, sd->entity.name, pad); > > >> ret = -EALREADY; > > >> goto done; > > >> } > > >> > > >> - dev_dbg(dev, "enable streams %u:%#llx\n", pad, streams_mask); > > >> + dev_dbg(dev, "enable streams %s:%u:%#llx\n", > > >> + sd->entity.name, pad, streams_mask); > > >> > > >> already_streaming = v4l2_subdev_is_streaming(sd); > > >> > > >> @@ -2333,8 +2334,8 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad, > > >> } > > >> > > >> if (ret) { > > >> - dev_dbg(dev, "enable streams %u:%#llx failed: %d\n", pad, > > >> - streams_mask, ret); > > >> + dev_err(dev, "enable streams %s:%u:%#llx failed: %d\n", > > >> + sd->entity.name, pad, streams_mask, ret); > > >> goto done; > > >> } > > >> > > >> @@ -2403,20 +2404,21 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad, > > >> &found_streams, &enabled_streams); > > >> > > >> if (found_streams != streams_mask) { > > >> - dev_dbg(dev, "streams 0x%llx not found on %s:%u\n", > > >> + dev_err(dev, "streams 0x%llx not found on %s:%u\n", > > >> streams_mask & ~found_streams, sd->entity.name, pad); > > >> ret = -EINVAL; > > >> goto done; > > >> } > > >> > > >> if (enabled_streams != streams_mask) { > > >> - dev_dbg(dev, "streams 0x%llx already disabled on %s:%u\n", > > >> + dev_err(dev, "streams 0x%llx already disabled on %s:%u\n", > > >> streams_mask & ~enabled_streams, sd->entity.name, pad); > > >> ret = -EALREADY; > > >> goto done; > > >> } > > >> > > >> - dev_dbg(dev, "disable streams %u:%#llx\n", pad, streams_mask); > > >> + dev_dbg(dev, "disable streams %s:%u:%#llx\n", > > >> + sd->entity.name, pad, streams_mask); > > >> > > >> if (!use_s_stream) { > > >> /* Call the .disable_streams() operation. */ > > >> @@ -2432,8 +2434,8 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad, > > >> } > > >> > > >> if (ret) { > > >> - dev_dbg(dev, "disable streams %u:%#llx failed: %d\n", pad, > > >> - streams_mask, ret); > > >> + dev_err(dev, "disable streams %s:%u:%#llx failed: %d\n", > > >> + sd->entity.name, pad, streams_mask, ret); > > >> goto done; > > >> } > > >> -- Regards, Sakari Ailus