On 9/2/25 9:52 AM, Ravulapalli, Naresh Kumar wrote:
On 30-Aug-25 5:30 AM, Marek Vasut wrote:
On 8/29/25 6:19 PM, Ravulapalli, Naresh Kumar wrote:
Hi Marek
On 29-Aug-25 2:11 PM, Marek Vasut wrote:
On 8/8/25 12:04 PM, Naresh Kumar Ravulapalli wrote:
Some USB devices need more time to be initialized. Hence,
increasing the default USB Hub debounce timeout value for
devices to be discovered, connected to Agilex5 boards.
Is this really hub debounce timeout or usb_pgood_delay ?
Which devices are those, include that in the commit message.
Yes, timeout is related to USB connect/disconnect signal bounces not
about bus stability during init.
Issue was mainly observed with legacy flash drives. Maybe I will change
commit text from "Some USB devices need more time to be initialized..."
to "Some old USB flash drives need more time to be initialized during
connect or disconnect events ..."?
Note that I am not modifying the default Kconfig value in general;
change is only made for an SoCFPGA devkit we tested.
Does this same issue go away if you set usb_pgood_delay to 2000 or
higher too ?
No, changing USB HUB debounce timeout is working for us.
Look at this code:
https://source.denx.de/u-boot/u-boot/-/blob/master/common/usb_hub.c?ref_type=heads#L199
"
#if CONFIG_IS_ENABLED(ENV_SUPPORT)
env = env_get("usb_pgood_delay");
if (env)
pgood_delay = max(pgood_delay,
(unsigned)simple_strtol(env, NULL, 0));
#endif
debug("pgood_delay=%dms\n", pgood_delay);
/*
* Do a minimum delay of the larger value of 100ms or pgood_delay
* so that the power can stablize before the devices are queried
*/
hub->query_delay = get_timer(0) + max(100, (int)pgood_delay);
/*
* Record the power-on timeout here. The max. delay (timeout)
* will be done based on this value in the USB port loop in
* usb_hub_configure() later.
*/
hub->connect_timeout = hub->query_delay + HUB_DEBOUNCE_TIMEOUT;
debug("devnum=%d poweron: query_delay=%d connect_timeout=%d\n",
dev->devnum, max(100, (int)pgood_delay),
max(100, (int)pgood_delay) + HUB_DEBOUNCE_TIMEOUT);
"
Changing both usb_pgood_delay or (CONFIG_USB_)HUB_DEBOUNCE_TIMEOUT
should have the same effect. How come it does not ?
