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SubjectRe: [PATCH 2/2] extcon: axp288: Only reschedule charger-detection at boot when a SDP is detected
On 2018년 01월 15일 17:36, Hans de Goede wrote:
> Hi,
>
> On 15-01-18 06:22, Chanwoo Choi wrote:
>> On 2018년 01월 15일 00:10, Hans de Goede wrote:
>>> The only misdetection which can happen at boot due to data-lines mux issues
>>> is detecting a non SDP as SDP, so we only need to retry if we detect a SDP
>>> on our first detection.
>>>
>>> Note Vbus misdetection is not a problem, as soon as the drivers controlling
>>> the Vbus path set it correctly we will get an interrupt which reschedules
>>> the charger-detection.
>>>
>>> Also update the comment about the re-detection to reflect this.
>>>
>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>> ---
>>> drivers/extcon/extcon-axp288.c | 14 +++++++-------
>>> 1 file changed, 7 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
>>> index 63b99d5becd7..17e6808af0d1 100644
>>> --- a/drivers/extcon/extcon-axp288.c
>>> +++ b/drivers/extcon/extcon-axp288.c
>>> @@ -161,16 +161,16 @@ static void axp288_chrg_detect_complete(struct axp288_extcon_info *info,
>>> /*
>>> * We depend on other drivers to do things like mux the data lines,
>>> * enable/disable vbus based on the id-pin, etc. Sometimes the BIOS has
>>> - * not set these things up correctly resulting in the initial charger
>>> - * cable type detection giving a wrong result and we end up not charging
>>> - * or charging at only 0.5A.
>>> + * not set these things up correctly resulting in a wrong result for the
>>> + * initial charger type detection and we end up charging at only 0.5A.
>>> *
>>> - * So we schedule a second cable type detection after 2 seconds to
>>> - * give the other drivers time to load and do their thing.
>>> + * If our first detect detects an SDP charger-type, we try again after
>>> + * 2 seconds to give the other drivers time to load and do their thing.
>>> */
>>> if (!info->first_detect_done) {
>>> - queue_delayed_work(system_wq, &info->det_work,
>>> - msecs_to_jiffies(2000));
>>> + if (info->previous_cable == EXTCON_CHG_USB_SDP)
>>> + queue_delayed_work(system_wq, &info->det_work,
>>> + msecs_to_jiffies(2000));
>>> info->first_detect_done = true;
>>> }
>>>
>>
>> I understand why you add the second delayed_work because of dependency
>> of other consumer driver. But, this patch is not proper method. It looks
>> like the workaround.
>>
>> We need to consider the fundamental solution such as using OF graph
>> or sending the pending notification when consumer driver is probed.
>
> I agree that having some sort of proper probe ordering here would be
> better. But on these ACPI systems that is going to be quite tricky todo,
> since we've no control over the firmware there.
>
> Note that you've already merged the workaround, this patch merely changes
> the workaround to avoid it in cases where it is not necessary, so I would
> really like to see this get merged.

I merged your patch because I knew this issue related to dependency.

But, I don't want to merge this patch until developing the fundamental
method. All extcon provider driver have the same issue. I'll try to
resolve this issue thro extcon framework.

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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