The branch main has been updated by imp:
URL:
https://cgit.FreeBSD.org/src/commit/?id=77054a897f6440632267e75ebe31793c7555b79e
commit 77054a897f6440632267e75ebe31793c7555b79e
Author: Warner Losh <i...@freebsd.org>
AuthorDate: 2021-10-01 15:53:10 +0000
Commit: Warner Losh <i...@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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