Hi, On 9/28/26 2:08 PM, Christian Berry wrote: > On 9/28/26 10:19, Ahmad Fatoum wrote: > > Nitpick: I'd prefer mdelay(1); but you don't need to resend just for this. > > Thanks for the response, > > I went with udelay(1000) intentionally, to mirror Linux's > usleep_range(1000, 2000) in the equivalent NVMe readiness poll > (commit 3e98c2443f5c). mdelay(1) would work too, and I did consider > it over udelay(1000) but keeping the barebox and Linux implementations > easy to compare side by side seemed worth it. Happy to switch if you > feel strongly; otherwise, I'll leave it as-is per your note.
Fair enough. Thanks for the elaboration! Cheers, Ahmad > > Thanks again, > Christian > > > On Mon, Sep 28, 2026 at 4:18 AM Ahmad Fatoum <[email protected]> wrote: >> >> On 9/28/26 1:03 AM, Christian Berry via B4 Relay wrote: >>> From: Christian Berry <[email protected]> >>> >>> nvme_wait_ready() polls the controller status every 100ms, although >>> the controller may become ready much sooner. Every probe then waits >>> at least 100ms longer than needed, and possibly twice, since both >>> nvme_disable_ctrl() and nvme_enable_ctrl() wait for readiness. >>> >>> Poll every millisecond instead, as Linux does since commit >>> 3e98c2443f5c ("nvme: Check for readiness more quickly, to speed up >>> boot time"). The overall timeout is still based on elapsed time, so >>> it is unaffected. >>> >>> Tested on an Arm64 SoC with a Samsung 980 SSD in a Gen3 x4 >>> configuration, where PCIe + NVMe probe time dropped from 165 ms to >>> 65 ms. >>> >>> Signed-off-by: Christian Berry <[email protected]> >> >> Reviewed-by: Ahmad Fatoum <[email protected]> >> >>> --- >>> drivers/nvme/host/core.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c >>> index 345707ecfe..9686268d44 100644 >>> --- a/drivers/nvme/host/core.c >>> +++ b/drivers/nvme/host/core.c >>> @@ -173,7 +173,7 @@ static int nvme_wait_ready(struct nvme_ctrl *ctrl, u64 >>> cap, bool enabled) >>> if ((csts & NVME_CSTS_RDY) == bit) >>> break; >>> >>> - mdelay(100); >>> + udelay(1000); >> >> Nitpick: I'd prefer mdelay(1); but you don't need to resend just for this. >> >> Cheers, >> Ahmad >> >>> >>> if (is_timeout(start, timeout)) { >>> dev_err(ctrl->dev, >>> >>> --- >>> base-commit: 983608b439b803f72f12d56d0ab10bd6ba29e536 >>> change-id: 20260927-nvme-ready-poll-4bd640377bab >>> >>> Best regards, >> >> -- >> Pengutronix e.K. | | >> Steuerwalder Str. 21 | http://www.pengutronix.de/ | >> 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | >> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | >> -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
