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| author | Erkka Talvitie <erkka.talvitie@vincit.fi> | 2019-12-11 11:08:39 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-17 18:02:49 +0300 |
| commit | 64cc3f12d1c7dd054a215bc1ff9cc2abcfe35832 (patch) | |
| tree | 4379634b21681f012e956b64617cf0cd1ef4c528 /drivers/usb | |
| parent | 547fc228755d79af648898187e7831a825d4f42c (diff) | |
| download | linux-64cc3f12d1c7dd054a215bc1ff9cc2abcfe35832.tar.xz | |
USB: EHCI: Do not return -EPIPE when hub is disconnected
When disconnecting a USB hub that has some child device(s) connected to it
(such as a USB mouse), then the stack tries to clear halt and
reset device(s) which are _already_ physically disconnected.
The issue has been reproduced with:
CPU: IMX6D5EYM10AD or MCIMX6D5EYM10AE.
SW: U-Boot 2019.07 and kernel 4.19.40.
CPU: HP Proliant Microserver Gen8.
SW: Linux version 4.2.3-300.fc23.x86_64
In this situation there will be error bit for MMF active yet the
CERR equals EHCI_TUNE_CERR + halt. Existing implementation
interprets this as a stall [1] (chapter 8.4.5).
The possible conditions when the MMF will be active + halt
can be found from [2] (Table 4-13).
Fix for the issue is to check whether MMF is active and PID Code is
IN before checking for the stall. If these conditions are true then
it is not a stall.
What happens after the fix is that when disconnecting a hub with
attached device(s) the situation is not interpret as a stall.
[1] [https://www.usb.org/document-library/usb-20-specification, usb_20.pdf]
[2] [https://www.intel.com/content/dam/www/public/us/en/documents/
technical-specifications/ehci-specification-for-usb.pdf]
Signed-off-by: Erkka Talvitie <erkka.talvitie@vincit.fi>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/ef70941d5f349767f19c0ed26b0dd9eed8ad81bb.1576050523.git.erkka.talvitie@vincit.fi
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/host/ehci-q.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index aa2f77f1506d..8a5c9b3ebe1e 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -27,6 +27,10 @@ /*-------------------------------------------------------------------------*/ +/* PID Codes that are used here, from EHCI specification, Table 3-16. */ +#define PID_CODE_IN 1 +#define PID_CODE_SETUP 2 + /* fill a qtd, returning how much of the buffer we were able to queue up */ static int @@ -190,7 +194,7 @@ static int qtd_copy_status ( int status = -EINPROGRESS; /* count IN/OUT bytes, not SETUP (even short packets) */ - if (likely (QTD_PID (token) != 2)) + if (likely(QTD_PID(token) != PID_CODE_SETUP)) urb->actual_length += length - QTD_LENGTH (token); /* don't modify error codes */ @@ -206,6 +210,13 @@ static int qtd_copy_status ( if (token & QTD_STS_BABBLE) { /* FIXME "must" disable babbling device's port too */ status = -EOVERFLOW; + /* + * When MMF is active and PID Code is IN, queue is halted. + * EHCI Specification, Table 4-13. + */ + } else if ((token & QTD_STS_MMF) && + (QTD_PID(token) == PID_CODE_IN)) { + status = -EPROTO; /* CERR nonzero + halt --> stall */ } else if (QTD_CERR(token)) { status = -EPIPE; |