On Thu, Nov 10, 2022, Ferry Toth wrote: > Hi > > Op 10-11-2022 om 13:45 schreef Ferry Toth: > > (sorry sent html with previous attempt) > > > > On 10-11-2022 01:06, Thinh Nguyen wrote: > > > Hi Ferry, > > > > > > On Wed, Nov 09, 2022, 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. Due to the timeout being masked dwc3 probe continues by > > > > calling dwc3_core_soft_reset() followed by dwc3_get_extcon() > > > > which happens > > > > to return -EPROBE_DEFER. On deferred probe ulpi_read_id() > > > > finally succeeds. > > > > > > > > This patch changes ulpi_read_id() to return -ETIMEDOUT when it > > > > occurs and > > > > catches the error in dwc3_core_init(). It handles the error by calling > > > > dwc3_core_soft_reset() after which it requests -EPROBE_DEFER. On > > > > deferred > > > > probe ulpi_read_id() again succeeds. > > > > > > > > Signed-off-by: Ferry Toth<ftoth@xxxxxxxxxxxxxx> > > > > --- > > > > drivers/usb/common/ulpi.c | 5 +++-- > > > > drivers/usb/dwc3/core.c | 5 ++++- > > > > 2 files changed, 7 insertions(+), 3 deletions(-) > > > > > > > Can you split the dwc3 change and ulpi change to separate patches? > > > > Thanks for your comments. > > > > I will send v2 > > > > > > diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c > > > > index d7c8461976ce..d8f22bc2f9d0 100644 > > > > --- a/drivers/usb/common/ulpi.c > > > > +++ b/drivers/usb/common/ulpi.c > > > > @@ -206,8 +206,9 @@ static int ulpi_read_id(struct ulpi *ulpi) > > > > /* Test the interface */ > > > > ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa); > > > > - if (ret < 0) > > > > - goto err; > > > > + if (ret < 0) { > > > > + return ret; > > > > + } > > > > ret = ulpi_read(ulpi, ULPI_SCRATCH); > > > > if (ret < 0) > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > > > index 648f1c570021..e293ef70039b 100644 > > > > --- a/drivers/usb/dwc3/core.c > > > > +++ b/drivers/usb/dwc3/core.c > > > > @@ -1106,8 +1106,11 @@ static int dwc3_core_init(struct dwc3 *dwc) > > > > if (!dwc->ulpi_ready) { > > > > ret = dwc3_core_ulpi_init(dwc); > > > > - if (ret) > > > > + if (ret) { > > > > + dwc3_core_soft_reset(dwc); > > > We shouldn't need to do soft reset here. The controller shouldn't be at > > > a bad/incorrect state at this point to warrant a soft-reset. There will > > > be a soft-reset when it goes through the initialization again. > > > > It doesn't go through the initialization again unless we set > > -EPROBE_DEFER. And when we make ulpi_read_id() return -EPROBE_DEFER it > > will goto err0 here, so skips dwc3_core_soft_reset. > > > > Do you mean you prefer something like: > > > > if (ret) { > > > > if (ret == -ETIMEDOUT) ret = -EPROBE_DEFER; > > > > else goto err0; Why "else"? But I saw you remove that in the new patch. > > > > } > > I just tested, and calling dwc3_core_soft_reset() proves to be necessary as > we need to goto err0 directly after. Else ret is overwritten and > -EPROBE_DEFER lost. Looks like there's a strange dependency problem here. * The setup needs a soft-reset before ulpi registration * The ulpi registration needs to go before the phy initialization * The soft-reset should be called after the phy initialization I can't explain the actual issue here, and we can't debug further because to look into it further would require looking at internal signals. This soft-reset and -EPROBE_DEFER seems to be a workaround to this dependency problem. Instead of using -EPROBE_DEFER, can you do this: diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 2f0a9679686f..5a1aaf3741ec 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1097,6 +1097,8 @@ static int dwc3_core_init(struct dwc3 *dwc) goto err0; if (!dwc->ulpi_ready) { + /* Add comment */ + dwc3_core_soft_reset(dwc); ret = dwc3_core_ulpi_init(dwc); if (ret) goto err0; > > > > > + ret = -EPROBE_DEFER; > > > We shouldn't automatically set every error status to correspond to > > > -EPROBE_DEFER. Check only the approapriate error codes (-ETIMEDOUT + > > > any other?). > > Other could be -ENOMEM. I think no need to do any new handling for that. There's also -EINVAL and some others too. Regardless, if it's -ENOMEM, then it should not return -EPROBE_DEFER. > > > > goto err0; > > > > + } > > > > dwc->ulpi_ready = true; > > > > } > > > > Thanks, Thinh