Date: Thu, 3 Jun 2021 01:49:03 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: e7dc08415a32 - main - mmc: ignore CRC errors from CMD13 (status) when changing rates Message-ID: <202106030149.1531n3xr086674@gitrepo.freebsd.org>
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The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=e7dc08415a324d1000cd067fbc12b1ec79e0b2ac commit e7dc08415a324d1000cd067fbc12b1ec79e0b2ac Author: Austin Shafer <ashafer@badland.io> AuthorDate: 2021-06-03 01:46:23 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2021-06-03 01:46:23 +0000 mmc: ignore CRC errors from CMD13 (status) when changing rates Update mmc_switch_status to ignore a few CRC errrors when asking for the card status after setting the new rate with CMD6. Since the card may take a little while to make the switch, it's possible we'll get a communications error if we sent the command at the wrong time. Several low end laptops needs this workaround as they have a window that seems longer than other systems. This is known to fix at least the Acer Aspire A114-32-P7E5. Reviewed by: imp@, manu@ Differential Revision: https://reviews.freebsd.org/D24740 --- sys/dev/mmc/mmc_subr.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/sys/dev/mmc/mmc_subr.c b/sys/dev/mmc/mmc_subr.c index 53c9009c6e64..b43a233820bb 100644 --- a/sys/dev/mmc/mmc_subr.c +++ b/sys/dev/mmc/mmc_subr.c @@ -193,7 +193,7 @@ int mmc_switch_status(device_t busdev, device_t dev, uint16_t rca, u_int timeout) { struct timeval cur, end; - int err; + int err, crc_timeout; uint32_t status; KASSERT(timeout != 0, ("%s: no timeout", __func__)); @@ -205,7 +205,19 @@ mmc_switch_status(device_t busdev, device_t dev, uint16_t rca, u_int timeout) */ end.tv_sec = end.tv_usec = 0; for (;;) { - err = mmc_send_status(busdev, dev, rca, &status); + crc_timeout=0; + do { + /* + * CRC errors indicate that the command wasn't accepted + * and executed due to a communications error. Retry + * CRC errors a couple of times to cope with transient + * failures. + * + * This is required for some cheap laptops to boot. + */ + err = mmc_send_status(busdev, dev, rca, &status); + crc_timeout++; + } while (err == MMC_ERR_BADCRC && crc_timeout < 10); if (err != MMC_ERR_NONE) break; if (R1_CURRENT_STATE(status) == R1_STATE_TRAN)
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