Re: [PATCH v2 1/2] usb: ulpi: defer ulpi_register on ulpi_read_id timeout

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Op 11-11-2022 om 07:08 schreef Greg Kroah-Hartman:
On Thu, Nov 10, 2022 at 10:11:31PM +0100, Ferry Toth wrote:
Since commit 0f010171
Dual Role support on Intel Merrifield platform broke due to rearranging
the call to dwc3_get_extcon().

Please see the kernel documentation for how to refer to commits.  This
should be written as:

	Since commit 0f0101719138 ("usb: dwc3: Don't switch OTG -> peripheral if
	extcon is present"), Dual role....

Thanks I'll fix that in v3.

It appears to be caused by ulpi_read_id() on the first test write failing
with -ETIMEDOUT. Currently ulpi_read_id() expects to discover the phy via
DT when the test write fails and returns 0 in that case even if DT does not
provide the phy. As a result usb probe completes without phy.

Signed-off-by: Ferry Toth <ftoth@xxxxxxxxxxxxxx>

What commit does this fix?

It's complicated, not sure how to explain this clearly:
ef6a7bcfb01c ("usb: ulpi: Support device discovery via DT") started to hide -ETIMEDOUT by returning 0. That problem was hidden due to another problem causing dwc3 to be deferred. But not properly, causing an infinite probe loop. This was fixed for quite some time by an out of tree patch. Now 0f0101719138 ("usb: dwc3: Don't switch OTG -> peripheral if extcon is present") accidentally fixes the probe loop, makes the out tree patch obsolete, but exposes the initial problem.

In short this patch fixes ef6a7bcfb01c ("usb: ulpi: Support device discovery via DT") by returning -ETIMEDOUT to its user, who should handle it appropriately. In case of dwc3 probe it sets -EPROBE_DEFER and bails out.

I'll add the short fixes: in v3.

Should this also get a cc: stable?

I will add.

thanks,

greg k-h




[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux