jerpelea opened a new pull request, #20264: URL: https://github.com/apache/nuttx/pull/20264
## Summary stm32_c22_read() and stm32_c22_write() waited for the MACMDIOAR busy bit with up_mdelay(5) between checks. A Clause 22 frame takes about 30 us, so the first check always sees the bus busy and every PHY register access costs a 5 ms busy-wait, roughly 150 times the transfer. stm32_phyinit() waits for link-up with PHY_RETRY_TIMEOUT (6552) MSR reads. With no cable attached that is 33 s of CPU spent in up_mdelay() inside ifup, with the network lock held: on an STM32H753 the netinit thread pinned the core at 44% for the first 65 s after boot and every socket operation on other threads blocked until it gave up. Before the MDIO bus refactor, stm32_phyread() polled the busy bit in a tight loop. Poll every 10 us instead, with the timeout expressed in microseconds so the total bound stays at 10 ms, and report the timeout from the result rather than the loop counter so a transfer that completes on the last iteration is not logged as timed out. ## Impact RELEASE ## Testing CI -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
