Messages in this thread | | | Subject | Re: [PATCH v3] driver core: Break infinite loop when deferred probe can't be satisfied | From | Grant Likely <> | Date | Thu, 26 Mar 2020 13:45:50 +0000 |
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On 26/03/2020 12:03, Andy Shevchenko wrote: > On Thu, Mar 26, 2020 at 11:45:18AM +0200, Peter Ujfalusi wrote: >> On 26/03/2020 10.39, Rafael J. Wysocki wrote: >>> On Wed, Mar 25, 2020 at 11:09 PM Saravana Kannan <saravanak@google.com> wrote: >>>> On Wed, Mar 25, 2020 at 5:51 AM Andy Shevchenko >>>> <andriy.shevchenko@linux.intel.com> wrote: > > ... > >>> OK, so the situation right now is that commit 58b116bce136 has >>> introduced a regression and so it needs to be fixed or reverted. The >>> cases that were previously broken and were unbroken by that commit >>> don't matter here, so you cannot argue that they would be "broken". >> >> commit 58b116bce136 is from 2014 and the whole ULPI support for dwc3 >> came in a year later. >> While I agree that 58b116bce136 fail to handle came a year later, but >> technically it did not introduced a regression. >> >> The revert on the other hand is going to introduce a regression as >> things were working fine since 2014. Not sure why the dwc3 issue got >> this long to be noticed as the 58b116bce136 was already in kernel when >> the ULPI support was added... > > I dare to say that is luck based on people's laziness to figure out the root > cause. As I pointed out in email to Saravana the issue is not limited to USB > case and, if my memory doesn't trick me out, I suffered from it approximately > in ~2014-2015 with pin control tables.
I've not been involved in this for a very long time, but from our past conversations and the description that is given here I still feel that this problem is a design bug on the dwc3 driver dependencies rather than a failure with driver core. dwc3 is doing something rather convoluted and it would be worth reevaluating how probe failures are unwound on that particular driver stack.
g.
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