Hi Balaji, On Tue, Oct 13, 2026 at 22:19, Balaji Selvanathan <[email protected]> wrote:
> Hi Mattijs, > > Sorry for late reply. > > On 7/24/2026 7:12 PM, Mattijs Korpershoek wrote: >> Hi Balaji, >> >> Thank you for the patch. >> >> On Fri, Jul 24, 2026 at 14:58, Balaji Selvanathan >> <[email protected]> wrote: >> >>> This reverts commit 6de333b5caf035c38d7af9fa7596aeffcc49db42. >>> >>> The delay is unnecessary. Upstream Linux does not add this delay after >>> the core soft reset and the USB works fine without it. >>> >>> Tested in QCS6490 RB3Gen2 Qualcomm board. >>> >>> Signed-off-by: Balaji Selvanathan <[email protected]> >>> --- >>> - This is part of ongoing initiative to reduce boot time across all >>> Qualcomm boards. So we can remove this unnecessary delay. >>> - Actually, this delay was removed in the Kodiak v4 series: >>> >>> https://lore.kernel.org/u-boot/[email protected]/ >>> but v3 series got picked up: >>> https://lore.kernel.org/u-boot/177745255938.126665.16625119085748603933.b4-ty@b4/ >>> --- >>> drivers/usb/dwc3/core.c | 2 -- >>> 1 file changed, 2 deletions(-) >>> >>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c >>> index be198041f08..ae22e1c792d 100644 >>> --- a/drivers/usb/dwc3/core.c >>> +++ b/drivers/usb/dwc3/core.c >>> @@ -106,8 +106,6 @@ done: >>> if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A)) >>> mdelay(50); >>> >>> - mdelay(100); >>> - >> The dwc3 driver is not only used by qualcomm, but many other SoCs. >> >> That delay indeed does not exist as is in the Linux driver since the >> following commit f59dcab17629 ("usb: dwc3: core: improve reset sequence") > > Yes, this delay doesn't exist in Linux driver and the delay was added by > me in 6de333b5caf035c38d7af9fa7596aeffcc49db42. > > But found later that this delay is actually not required and hence would > like to revert it. Have tested the revert on QCM6490 and USB inits fine. > >> >> However, that commit is more conservative by adding retries and such. >> >> I'd prefer to stick with Linux's approach here. >> >> Also note, there is an ongoing effort of updating the dwc3 driver by >> Linaro here: >> >> https://lore.kernel.org/all/[email protected]/ >> >> Could you maybe give that a try? It should have the >> "usb: dwc3: core: improve reset sequence" patch in there. > I agree the Linaro series is the right long-term fix, since it carries > the retry-based approach from Linux rather than a flat delay. > That series touches a fair amount of the reset sequence though, and it > may take a while to land upstream. > > Given that, would you be open to taking this revert now as an interim > fix, since it's tested not to regress the platform it was added for? No, I'd like that we (as a community) spend time to do the right long-term fix. Please consider testing Ander's series (latest is v10 here: https://lore.kernel.org/all/[email protected]/) Testing on hardware is very useful and will help to include the long term fix from Anders Thanks Mattijs > > Regards, > > Balaji > >> >>> return 0; >>> } >>> >>> >>> --- >>> base-commit: d7ef23c07b8e34f65b3e15e3b4e7f58d074923c8 >>> change-id: 20260724-kodiak_delay-a5f1e8b675cd >>> >>> Best regards, >>> -- >>> Balaji Selvanathan <[email protected]>
