Date: Fri, 1 Oct 2021 16:56:25 GMT From: Warner Losh <imp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 77054a897f64 - main - nvme: Explain a workaround a little better Message-ID: <202110011656.191GuPrA004105@gitrepo.freebsd.org>
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The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=77054a897f6440632267e75ebe31793c7555b79e commit 77054a897f6440632267e75ebe31793c7555b79e Author: Warner Losh <imp@FreeBSD.org> AuthorDate: 2021-10-01 15:53:10 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2021-10-01 16:56:10 +0000 nvme: Explain a workaround a little better The don't touch the mmio of the drive after we do a EN 1->0 transition is only for a tiny number of dirves that have this unforunate issue. Sponsored by: Netflix --- sys/dev/nvme/nvme_ctrlr.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c index 10b30c584f71..eb95fa33b90b 100644 --- a/sys/dev/nvme/nvme_ctrlr.c +++ b/sys/dev/nvme/nvme_ctrlr.c @@ -318,10 +318,10 @@ nvme_ctrlr_disable(struct nvme_controller *ctrlr) cc &= ~NVME_CC_REG_EN_MASK; nvme_mmio_write_4(ctrlr, cc, cc); + /* - * Some drives have issues with accessing the mmio after we - * disable, so delay for a bit after we write the bit to - * cope with these issues. + * A few drives have firmware bugs that freeze the drive if we access + * the mmio too soon after we disable. */ if (ctrlr->quirks & QUIRK_DELAY_B4_CHK_RDY) pause("nvmeR", MSEC_2_TICKS(B4_CHK_RDY_DELAY_MS));
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