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authorErkka Talvitie <erkka.talvitie@vincit.fi>2019-12-11 11:08:39 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-12-17 18:02:49 +0300
commit64cc3f12d1c7dd054a215bc1ff9cc2abcfe35832 (patch)
tree4379634b21681f012e956b64617cf0cd1ef4c528 /drivers/usb
parent547fc228755d79af648898187e7831a825d4f42c (diff)
downloadlinux-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.c13
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;