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mmc: ignore CRC errors from CMD13 (status) when changing rates

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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
This commit is contained in:
Austin Shafer 2021-06-02 19:46:23 -06:00 committed by Warner Losh
parent 9a0f822853
commit e7dc08415a
1 changed files with 14 additions and 2 deletions
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16
sys/dev/mmc/mmc_subr.c
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@ -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)