diff mbox series

[v2] HID: i2c-hid: use print_hex_dump_debug to print report descriptor

Message ID OS3P286MB259916DCE3D992135FF05F4CB115A@OS3P286MB2599.JPNP286.PROD.OUTLOOK.COM (mailing list archive)
State Superseded
Delegated to: Jiri Kosina
Headers show
Series [v2] HID: i2c-hid: use print_hex_dump_debug to print report descriptor | expand

Commit Message

Riwen Lu Aug. 16, 2023, 8:38 a.m. UTC 
From: Riwen Lu <luriwen@kylinos.cn>

The format '%*ph' print up to 64 bytes long as a hex string with ' '
sepatator. Usually the size of report descriptor is larger than 64
bytes, so consider using print_hex_dump_debug to print out all of it for
better debugging.

Signed-off-by: Riwen Lu <luriwen@kylinos.cn>

---
v1->v2:
 - Add a prefix for the hex dump.
---
 drivers/hid/i2c-hid/i2c-hid-core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Rahul Rameshbabu Aug. 17, 2023, 4:25 a.m. UTC | #1 
On Wed, 16 Aug, 2023 16:38:19 +0800 "Riwen Lu" <luriwen@hotmail.com> wrote:
> From: Riwen Lu <luriwen@kylinos.cn>
>
> The format '%*ph' print up to 64 bytes long as a hex string with ' '
> sepatator. Usually the size of report descriptor is larger than 64
> bytes, so consider using print_hex_dump_debug to print out all of it for
> better debugging.
>
> Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
>
> ---
> v1->v2:
>  - Add a prefix for the hex dump.
> ---
>  drivers/hid/i2c-hid/i2c-hid-core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
> index efbba0465eef..fd82e9042da5 100644
> --- a/drivers/hid/i2c-hid/i2c-hid-core.c
> +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
> @@ -772,7 +772,9 @@ static int i2c_hid_parse(struct hid_device *hid)
>  		}
>  	}
>
> -	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
> +	i2c_hid_dbg(ihid, "Report Descriptor\n");

Instead of just indicating that the report descriptor dump begins with
the above print, I think it makes more sense for the print to be changed
to a pair of begin/end or "cut here" prints similar to what you see in
oops messages. This will help individuals reading reports copied by bug
reporters validate that the complete descriptor dump is present.

Something along the lines of what is done in sound/soc/sof/debug.c.

  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/sof/debug.c?id=4853c74bd7ab7fdb83f319bd9ace8a08c031e9b6#n407

> +	print_hex_dump_debug("Report Descriptor: ", DUMP_PREFIX_OFFSET, 16, 1,
> +			rdesc, rsize, false);
>

--
Thanks,

Rahul Rameshbabu
Riwen Lu Aug. 23, 2023, 8:03 a.m. UTC | #2 
在 2023/8/17 12:25, Rahul Rameshbabu 写道:
> 
> On Wed, 16 Aug, 2023 16:38:19 +0800 "Riwen Lu" <luriwen@hotmail.com> wrote:
>> From: Riwen Lu <luriwen@kylinos.cn>
>>
>> The format '%*ph' print up to 64 bytes long as a hex string with ' '
>> sepatator. Usually the size of report descriptor is larger than 64
>> bytes, so consider using print_hex_dump_debug to print out all of it for
>> better debugging.
>>
>> Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
>>
>> ---
>> v1->v2:
>>   - Add a prefix for the hex dump.
>> ---
>>   drivers/hid/i2c-hid/i2c-hid-core.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
>> index efbba0465eef..fd82e9042da5 100644
>> --- a/drivers/hid/i2c-hid/i2c-hid-core.c
>> +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
>> @@ -772,7 +772,9 @@ static int i2c_hid_parse(struct hid_device *hid)
>>   		}
>>   	}
>>
>> -	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
>> +	i2c_hid_dbg(ihid, "Report Descriptor\n");
> 
> Instead of just indicating that the report descriptor dump begins with
> the above print, I think it makes more sense for the print to be changed
> to a pair of begin/end or "cut here" prints similar to what you see in
> oops messages. This will help individuals reading reports copied by bug
> reporters validate that the complete descriptor dump is present.
> 
> Something along the lines of what is done in sound/soc/sof/debug.c.
> 
I don't think it's necessary to add a pair of begin/end prints like 
that. However, I can print out the size of the report descriptor through 
i2c_hid_dbg. And print_hex_dump_debug prints each line with a "Report 
Descriptor" prefix and an offset, so it's easy to know if the descriptor 
dump is complete.
The dump message is similar to the following.
i2c_hid i2c-PNP0C50:00: Report Descriptor size: 0x144
Report Descriptor: 00000000: 05 01 09 02 a1 01 85 01 09 01 a1 00 05 09 19 01
Report Descriptor: 00000010: 29 02 15 00 25 01 75 01 95 02 81 02 95 06 81 03
Report Descriptor: 00000020: 05 01 09 30 09 31 09 38 15 81 25 7f 75 08 95 03
Report Descriptor: 00000030: 81 06 c0 c0 05 0d 09 05 a1 01 85 04 09 22 a1 02
Report Descriptor: 00000040: 15 00 25 01 09 47 09 42 95 02 75 01 81 02 95 01
Report Descriptor: 00000050: 75 03 25 02 09 51 81 02 75 01 95 03 81 03 05 01
Report Descriptor: 00000060: 15 00 26 5b 05 75 10 55 0d 65 11 09 30 35 00 46
Report Descriptor: 00000070: 46 2a 95 01 81 02 46 59 17 26 f4 02 09 31 81 02
Report Descriptor: 00000080: 05 0d 15 00 25 64 95 03 c0 55 0c 66 01 10 47 ff
Report Descriptor: 00000090: ff 00 00 27 ff ff 00 00 75 10 95 01 09 56 81 02
Report Descriptor: 000000a0: 09 54 25 7f 95 01 75 08 81 02 05 09 09 01 25 01
Report Descriptor: 000000b0: 75 01 95 01 81 02 95 07 81 03 09 c5 75 20 95 01
Report Descriptor: 000000c0: 81 03 05 0d 85 02 09 55 09 59 75 04 95 02 25 0f
Report Descriptor: 000000d0: b1 02 85 07 09 60 75 01 95 01 15 00 25 01 b1 02
Report Descriptor: 000000e0: 95 07 b1 03 06 00 ff 85 08 09 c5 15 00 26 ff 00
Report Descriptor: 000000f0: 75 08 96 00 01 b1 02 c0 05 0d 09 0e a1 01 85 03
Report Descriptor: 00000100: 09 22 a1 02 09 52 15 00 25 0a 75 08 95 01 b1 02
Report Descriptor: 00000110: c0 09 22 a1 00 85 05 09 57 09 58 75 01 95 02 25
Report Descriptor: 00000120: 03 b1 02 95 06 b1 03 c0 c0 06 00 ff 09 01 a1 01
Report Descriptor: 00000130: 15 00 26 ff 00 75 08 85 06 95 3f 09 01 81 02 09
Report Descriptor: 00000140: 01 91 02 c0

Thanks.

>    https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/sof/debug.c?id=4853c74bd7ab7fdb83f319bd9ace8a08c031e9b6#n407
> 
>> +	print_hex_dump_debug("Report Descriptor: ", DUMP_PREFIX_OFFSET, 16, 1,
>> +			rdesc, rsize, false);
>>
> 
> --
> Thanks,
> 
> Rahul Rameshbabu
>
Rahul Rameshbabu Aug. 26, 2023, 5:26 p.m. UTC | #3 
On Wed, 23 Aug, 2023 16:03:46 +0800 "Riwen Lu" <luriwen@hotmail.com> wrote:
> 在 2023/8/17 12:25, Rahul Rameshbabu 写道:
>>
>> On Wed, 16 Aug, 2023 16:38:19 +0800 "Riwen Lu" <luriwen@hotmail.com> wrote:
>>> From: Riwen Lu <luriwen@kylinos.cn>
>>>
>>> The format '%*ph' print up to 64 bytes long as a hex string with ' '

Cosmetic but if you are sending a v3 anyways, s/print/prints.

>>> sepatator. Usually the size of report descriptor is larger than 64

s/sepatator/separator

>>> bytes, so consider using print_hex_dump_debug to print out all of it for
>>> better debugging.
>>>
>>> Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
>>>
>>> ---
>>> v1->v2:
>>>   - Add a prefix for the hex dump.
>>> ---
>>>   drivers/hid/i2c-hid/i2c-hid-core.c | 4 +++-
>>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
>>> index efbba0465eef..fd82e9042da5 100644
>>> --- a/drivers/hid/i2c-hid/i2c-hid-core.c
>>> +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
>>> @@ -772,7 +772,9 @@ static int i2c_hid_parse(struct hid_device *hid)
>>>   		}
>>>   	}
>>>
>>> -	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
>>> +	i2c_hid_dbg(ihid, "Report Descriptor\n");
>>
>> Instead of just indicating that the report descriptor dump begins with
>> the above print, I think it makes more sense for the print to be changed
>> to a pair of begin/end or "cut here" prints similar to what you see in
>> oops messages. This will help individuals reading reports copied by bug
>> reporters validate that the complete descriptor dump is present.
>>
>> Something along the lines of what is done in sound/soc/sof/debug.c.
>>
> I don't think it's necessary to add a pair of begin/end prints like
> that. However, I can print out the size of the report descriptor through
> i2c_hid_dbg. And print_hex_dump_debug prints each line with a "Report
> Descriptor" prefix and an offset, so it's easy to know if the descriptor
> dump is complete.
> The dump message is similar to the following.

Yeah, I agree with this. My main concern was the fact that the
i2c_hid_dbg was not adding any value as-is aside from indicating what
driver is causing the dump (which could be appended to
print_hex_dump_debug). I like adding the size in the print.

> i2c_hid i2c-PNP0C50:00: Report Descriptor size: 0x144
> Report Descriptor: 00000000: 05 01 09 02 a1 01 85 01 09 01 a1 00 05 09 19 01
> Report Descriptor: 00000010: 29 02 15 00 25 01 75 01 95 02 81 02 95 06 81 03
> Report Descriptor: 00000020: 05 01 09 30 09 31 09 38 15 81 25 7f 75 08 95 03
> Report Descriptor: 00000030: 81 06 c0 c0 05 0d 09 05 a1 01 85 04 09 22 a1 02
> Report Descriptor: 00000040: 15 00 25 01 09 47 09 42 95 02 75 01 81 02 95 01
> Report Descriptor: 00000050: 75 03 25 02 09 51 81 02 75 01 95 03 81 03 05 01
> Report Descriptor: 00000060: 15 00 26 5b 05 75 10 55 0d 65 11 09 30 35 00 46
> Report Descriptor: 00000070: 46 2a 95 01 81 02 46 59 17 26 f4 02 09 31 81 02
> Report Descriptor: 00000080: 05 0d 15 00 25 64 95 03 c0 55 0c 66 01 10 47 ff
> Report Descriptor: 00000090: ff 00 00 27 ff ff 00 00 75 10 95 01 09 56 81 02
> Report Descriptor: 000000a0: 09 54 25 7f 95 01 75 08 81 02 05 09 09 01 25 01
> Report Descriptor: 000000b0: 75 01 95 01 81 02 95 07 81 03 09 c5 75 20 95 01
> Report Descriptor: 000000c0: 81 03 05 0d 85 02 09 55 09 59 75 04 95 02 25 0f
> Report Descriptor: 000000d0: b1 02 85 07 09 60 75 01 95 01 15 00 25 01 b1 02
> Report Descriptor: 000000e0: 95 07 b1 03 06 00 ff 85 08 09 c5 15 00 26 ff 00
> Report Descriptor: 000000f0: 75 08 96 00 01 b1 02 c0 05 0d 09 0e a1 01 85 03
> Report Descriptor: 00000100: 09 22 a1 02 09 52 15 00 25 0a 75 08 95 01 b1 02
> Report Descriptor: 00000110: c0 09 22 a1 00 85 05 09 57 09 58 75 01 95 02 25
> Report Descriptor: 00000120: 03 b1 02 95 06 b1 03 c0 c0 06 00 ff 09 01 a1 01
> Report Descriptor: 00000130: 15 00 26 ff 00 75 08 85 06 95 3f 09 01 81 02 09
> Report Descriptor: 00000140: 01 91 02 c0
>
> Thanks.
>
>>    https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/sof/debug.c?id=4853c74bd7ab7fdb83f319bd9ace8a08c031e9b6#n407
>>
>>> +	print_hex_dump_debug("Report Descriptor: ", DUMP_PREFIX_OFFSET, 16, 1,
>>> +			rdesc, rsize, false);
>>>
>>
--
Thanks,

Rahul Rameshbabu
diff mbox series

Patch

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index efbba0465eef..fd82e9042da5 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -772,7 +772,9 @@  static int i2c_hid_parse(struct hid_device *hid)
 		}
 	}
 
-	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
+	i2c_hid_dbg(ihid, "Report Descriptor\n");
+	print_hex_dump_debug("Report Descriptor: ", DUMP_PREFIX_OFFSET, 16, 1,
+			rdesc, rsize, false);
 
 	ret = hid_parse_report(hid, rdesc, rsize);
 	if (!use_override)