Re: [PATCH v7 2/4] driver core: add deferring probe reason to devices_deferred property
On Tue, Jun 30, 2020 at 11:32 AM Andrzej Hajda wrote: > On 29.06.2020 18:36, Andy Shevchenko wrote: > > On Mon, Jun 29, 2020 at 2:22 PM Andrzej Hajda wrote: > >> /sys/kernel/debug/devices_deferred property contains list of deferred > >> devices. > >> This list does not contain reason why the driver deferred probe, the patch > >> improves it. > >> The natural place to set the reason is dev_err_probe function introduced > >> recently, > >> ie. if dev_err_probe will be called with -EPROBE_DEFER instead of printk > >> the message > >> will be attached to deferred device and printed when user read > >> devices_deferred > > to a deferred > > > > reads > OK, thx. > > > >> property. ... > >> list_for_each_entry(curr, _probe_pending_list, > >> deferred_probe) > >> - seq_printf(s, "%s\n", dev_name(curr->device)); > >> + seq_printf(s, "%s\t%s", dev_name(curr->device), > >> + curr->device->p->deferred_probe_reason ?: "\n"); > > Hmm... "\t" will be dangling in the latter case > > > Hmm, I followed your advice [1] :) > > [1]: > https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1787370.html Ah, indeed :-) Okay, as I said I'm fine with the code. Since it's debugfs, we are fine. -- With Best Regards, Andy Shevchenko ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v7 2/4] driver core: add deferring probe reason to devices_deferred property
On 29.06.2020 18:36, Andy Shevchenko wrote:
> On Mon, Jun 29, 2020 at 2:22 PM Andrzej Hajda wrote:
>> /sys/kernel/debug/devices_deferred property contains list of deferred
>> devices.
>> This list does not contain reason why the driver deferred probe, the patch
>> improves it.
>> The natural place to set the reason is dev_err_probe function introduced
>> recently,
>> ie. if dev_err_probe will be called with -EPROBE_DEFER instead of printk the
>> message
>> will be attached to deferred device and printed when user read
>> devices_deferred
> to a deferred
>
> reads
OK, thx.
>
>> property.
> ...
>
>> @@ -3984,10 +3986,12 @@ int dev_err_probe(const struct device *dev, int err,
>> const char *fmt, ...)
>> vaf.fmt = fmt;
>> vaf.va =
>>
>> - if (err != -EPROBE_DEFER)
>> + if (err != -EPROBE_DEFER) {
> Why not positive conditional? (Okay, I'm fine with either in this case)
I put more natural branch 1st.
>
>> dev_err(dev, "error %d: %pV", err, );
>> - else
>> + } else {
>> + device_set_deferred_probe_reson(dev, );
>> dev_dbg(dev, "error %d: %pV", err, );
>> + }
> To reduce churn, you may move {} addition to the first patch.
But then I need to explain why it is there :)
>
> ...
>
>> list_for_each_entry(curr, _probe_pending_list,
>> deferred_probe)
>> - seq_printf(s, "%s\n", dev_name(curr->device));
>> + seq_printf(s, "%s\t%s", dev_name(curr->device),
>> + curr->device->p->deferred_probe_reason ?: "\n");
> Hmm... "\t" will be dangling in the latter case
Hmm, I followed your advice [1] :)
[1]:
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1787370.html
Regards
Andrzej
>
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v7 2/4] driver core: add deferring probe reason to devices_deferred property
On Mon, Jun 29, 2020 at 2:22 PM Andrzej Hajda wrote:
>
> /sys/kernel/debug/devices_deferred property contains list of deferred devices.
> This list does not contain reason why the driver deferred probe, the patch
> improves it.
> The natural place to set the reason is dev_err_probe function introduced
> recently,
> ie. if dev_err_probe will be called with -EPROBE_DEFER instead of printk the
> message
> will be attached to deferred device and printed when user read
> devices_deferred
to a deferred
reads
> property.
...
> @@ -3984,10 +3986,12 @@ int dev_err_probe(const struct device *dev, int err,
> const char *fmt, ...)
> vaf.fmt = fmt;
> vaf.va =
>
> - if (err != -EPROBE_DEFER)
> + if (err != -EPROBE_DEFER) {
Why not positive conditional? (Okay, I'm fine with either in this case)
> dev_err(dev, "error %d: %pV", err, );
> - else
> + } else {
> + device_set_deferred_probe_reson(dev, );
> dev_dbg(dev, "error %d: %pV", err, );
> + }
To reduce churn, you may move {} addition to the first patch.
...
> list_for_each_entry(curr, _probe_pending_list,
> deferred_probe)
> - seq_printf(s, "%s\n", dev_name(curr->device));
> + seq_printf(s, "%s\t%s", dev_name(curr->device),
> + curr->device->p->deferred_probe_reason ?: "\n");
Hmm... "\t" will be dangling in the latter case.
--
With Best Regards,
Andy Shevchenko
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
[PATCH v7 2/4] driver core: add deferring probe reason to devices_deferred property
/sys/kernel/debug/devices_deferred property contains list of deferred devices.
This list does not contain reason why the driver deferred probe, the patch
improves it.
The natural place to set the reason is dev_err_probe function introduced
recently,
ie. if dev_err_probe will be called with -EPROBE_DEFER instead of printk the
message
will be attached to deferred device and printed when user read devices_deferred
property.
Signed-off-by: Andrzej Hajda
Reviewed-by: Mark Brown
Reviewed-by: Javier Martinez Canillas
Reviewed-by: Andy Shevchenko
Reviewed-by: Rafael J. Wysocki
---
drivers/base/base.h | 3 +++
drivers/base/core.c | 8 ++--
drivers/base/dd.c | 23 ++-
3 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/drivers/base/base.h b/drivers/base/base.h
index 95c22c0f9036..6954fccab3d7 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -93,6 +93,7 @@ struct device_private {
struct klist_node knode_class;
struct list_head deferred_probe;
struct device_driver *async_driver;
+ char *deferred_probe_reason;
struct device *device;
u8 dead:1;
};
@@ -134,6 +135,8 @@ extern void device_release_driver_internal(struct device
*dev,
extern void driver_detach(struct device_driver *drv);
extern int driver_probe_device(struct device_driver *drv, struct device *dev);
extern void driver_deferred_probe_del(struct device *dev);
+extern void device_set_deferred_probe_reson(const struct device *dev,
+ struct va_format *vaf);
static inline int driver_match_device(struct device_driver *drv,
struct device *dev)
{
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 3a827c82933f..fee047f03681 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3963,6 +3963,8 @@ define_dev_printk_level(_dev_info, KERN_INFO);
* This helper implements common pattern present in probe functions for error
* checking: print debug or error message depending if the error value is
* -EPROBE_DEFER and propagate error upwards.
+ * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
+ * checked later by reading devices_deferred debugfs attribute.
* It replaces code sequence:
* if (err != -EPROBE_DEFER)
* dev_err(dev, ...);
@@ -3984,10 +3986,12 @@ int dev_err_probe(const struct device *dev, int err,
const char *fmt, ...)
vaf.fmt = fmt;
vaf.va =
- if (err != -EPROBE_DEFER)
+ if (err != -EPROBE_DEFER) {
dev_err(dev, "error %d: %pV", err, );
- else
+ } else {
+ device_set_deferred_probe_reson(dev, );
dev_dbg(dev, "error %d: %pV", err, );
+ }
va_end(args);
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 9a1d940342ac..dd5683b61f74 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -27,6 +27,7 @@
#include
#include
#include
+#include
#include "base.h"
#include "power/power.h"
@@ -136,6 +137,8 @@ void driver_deferred_probe_del(struct device *dev)
if (!list_empty(>p->deferred_probe)) {
dev_dbg(dev, "Removed from deferred list\n");
list_del_init(>p->deferred_probe);
+ kfree(dev->p->deferred_probe_reason);
+ dev->p->deferred_probe_reason = NULL;
}
mutex_unlock(_probe_mutex);
}
@@ -211,6 +214,23 @@ void device_unblock_probing(void)
driver_deferred_probe_trigger();
}
+/**
+ * device_set_deferred_probe_reson() - Set defer probe reason message for
device
+ * @dev: the pointer to the struct device
+ * @vaf: the pointer to va_format structure with message
+ */
+void device_set_deferred_probe_reson(const struct device *dev, struct
va_format *vaf)
+{
+ const char *drv = dev_driver_string(dev);
+
+ mutex_lock(_probe_mutex);
+
+ kfree(dev->p->deferred_probe_reason);
+ dev->p->deferred_probe_reason = kasprintf(GFP_KERNEL, "%s: %pV", drv,
vaf);
+
+ mutex_unlock(_probe_mutex);
+}
+
/*
* deferred_devs_show() - Show the devices in the deferred probe pending list.
*/
@@ -221,7 +241,8 @@ static int deferred_devs_show(struct seq_file *s, void
*data)
mutex_lock(_probe_mutex);
list_for_each_entry(curr, _probe_pending_list, deferred_probe)
- seq_printf(s, "%s\n", dev_name(curr->device));
+ seq_printf(s, "%s\t%s", dev_name(curr->device),
+ curr->device->p->deferred_probe_reason ?: "\n");
mutex_unlock(_probe_mutex);
--
2.17.1
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
