| Message ID | 20221110211132.297512-2-ftoth@exalondelft.nl (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: dwc3: core: defer probe on ulpi_read_id timeout | expand |
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.... > 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@exalondelft.nl> What commit does this fix? Should this also get a cc: stable? thanks, greg k-h
+ Stephen Boyd On 10-11-2022 22:11, Ferry Toth wrote: > Since commit 0f010171 > Dual Role support on Intel Merrifield platform broke due to rearranging > the call to dwc3_get_extcon(). > > 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@exalondelft.nl> > --- > drivers/usb/common/ulpi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c > index d7c8461976ce..60e8174686a1 100644 > --- a/drivers/usb/common/ulpi.c > +++ b/drivers/usb/common/ulpi.c > @@ -207,7 +207,7 @@ static int ulpi_read_id(struct ulpi *ulpi) > /* Test the interface */ > ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa); > if (ret < 0) > - goto err; > + return ret; > > ret = ulpi_read(ulpi, ULPI_SCRATCH); > if (ret < 0) Would this affect others phys (like qcom HSIC)? I'm not sure if failing the test write is a normal behavior.
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@exalondelft.nl> > > 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
Quoting Ferry Toth (2022-11-11 06:04:16) > + Stephen Boyd > > On 10-11-2022 22:11, Ferry Toth wrote: > > Since commit 0f010171 > > Dual Role support on Intel Merrifield platform broke due to rearranging > > the call to dwc3_get_extcon(). > > > > 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@exalondelft.nl> > > --- > > drivers/usb/common/ulpi.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c > > index d7c8461976ce..60e8174686a1 100644 > > --- a/drivers/usb/common/ulpi.c > > +++ b/drivers/usb/common/ulpi.c > > @@ -207,7 +207,7 @@ static int ulpi_read_id(struct ulpi *ulpi) > > /* Test the interface */ > > ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa); > > if (ret < 0) > > - goto err; > > + return ret; > > > > ret = ulpi_read(ulpi, ULPI_SCRATCH); > > if (ret < 0) > > Would this affect others phys (like qcom HSIC)? I'm not sure if failing > the test write is a normal behavior. I don't think failing a test write is normal behavior. I don't have this hardware on hand anymore though, so I can't help test it. Looks OK to me though: Reviewed-by: Stephen Boyd <sboyd@kernel.org>
diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c index d7c8461976ce..60e8174686a1 100644 --- a/drivers/usb/common/ulpi.c +++ b/drivers/usb/common/ulpi.c @@ -207,7 +207,7 @@ static int ulpi_read_id(struct ulpi *ulpi) /* Test the interface */ ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa); if (ret < 0) - goto err; + return ret; ret = ulpi_read(ulpi, ULPI_SCRATCH); if (ret < 0)
Since commit 0f010171 Dual Role support on Intel Merrifield platform broke due to rearranging the call to dwc3_get_extcon(). 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@exalondelft.nl> --- drivers/usb/common/ulpi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)