On 12/7/23 17:10, Dragan Simic wrote: > On 2023-12-07 10:25, Jensen Huang wrote: >> On Thu, Dec 7, 2023 at 4:37 PM Dragan Simic <dsimic@xxxxxxxxxxx> wrote: >>> >>> On 2023-12-07 09:21, Jensen Huang wrote: >>> > Possible deadlock scenario (on reboot): >>> > rk3x_i2c_xfer_common(polling) >>> > -> rk3x_i2c_wait_xfer_poll() >>> > -> rk3x_i2c_irq(0, i2c); >>> > --> spin_lock(&i2c->lock); >>> > ... >>> > <rk3x i2c interrupt> >>> > -> rk3x_i2c_irq(0, i2c); >>> > --> spin_lock(&i2c->lock); (deadlock here) >>> > >>> > Store the IRQ number and disable/enable it around the polling >>> transfer. >>> > This patch has been tested on NanoPC-T4. >>> >>> In case you haven't already seen the related discussion linked below, >>> please have a look. I also added more people to the list of recipients, >>> in an attempt to make everyone aware of the different approaches to >>> solving this issue. >>> >>> https://lore.kernel.org/all/655177f4.050a0220.d85c9.3ba0@xxxxxxxxxxxxx/T/#m6fc9c214452fec6681843e7f455978c35c6f6c8b >> >> Thank you for providing the information. I hadn't seen this link before. >> After carefully looking into the related discussion, it appears that >> Dmitry Osipenko is already working on a suitable patch. To avoid >> duplication >> or conflicts, my patch can be discarded. > > Thank you for responding so quickly. Perhaps it would be best to hear > from Dmitry as well, before discarding anything. It's been a while > since Dmitry wrote about working on the patch, so he might have > abandoned it. This patch is okay. In general, will be better to have IRQ disabled by default like I did in my variant, it should allow to remove the spinlock entirely. Of course this also can be done later on in a follow up patches. Jensen, feel free to use my variant of the patch, add my s-o-b+co-developed tags to the commit msg if you'll do. Otherwise I'll be able to send my patch next week. -- Best regards, Dmitry
