[PATCH v2] usb: typec: tcpm: fix multiple times discover svids error
linux at roeck-us.net
Thu Apr 20 06:49:03 PDT 2023
On 4/20/23 01:08, Greg KH wrote:
> On Fri, Mar 17, 2023 at 01:27:13PM +0200, Heikki Krogerus wrote:
>> On Thu, Mar 16, 2023 at 04:11:49PM +0800, Frank Wang wrote:
>>> PD3.0 Spec 184.108.40.206.2 say that only Responder supports 12 or more SVIDs,
>>> the Discover SVIDs Command Shall be executed multiple times until a
>>> Discover SVIDs VDO is returned ending either with a SVID value of
>>> 0x0000 in the last part of the last VDO or with a VDO containing two
>>> SVIDs with values of 0x0000.
>>> In the current implementation, if the last VDO does not find that the
>>> Discover SVIDs Command would be executed multiple times even if the
>>> Responder SVIDs are less than 12, and we found some odd dockers just
>>> meet this case. So fix it.
>>> Signed-off-by: Frank Wang <frank.wang at rock-chips.com>
>>> drivers/usb/typec/tcpm/tcpm.c | 16 +++++++++++++++-
>>> 1 file changed, 15 insertions(+), 1 deletion(-)
>>> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
>>> index 66de02a56f512..a3ae2c79f3540 100644
>>> --- a/drivers/usb/typec/tcpm/tcpm.c
>>> +++ b/drivers/usb/typec/tcpm/tcpm.c
>>> @@ -1515,7 +1515,21 @@ static bool svdm_consume_svids(struct tcpm_port *port, const u32 *p, int cnt)
>>> pmdata->svids[pmdata->nsvids++] = svid;
>>> tcpm_log(port, "SVID %d: 0x%x", pmdata->nsvids, svid);
>>> - return true;
>>> + /*
>>> + * PD3.0 Spec 220.127.116.11.2: The SVIDs are returned 2 per VDO (see Table
>>> + * 6-43), and can be returned maximum 6 VDOs per response (see Figure
>>> + * 6-19). If the Respondersupports 12 or more SVID then the Discover
>>> + * SVIDs Command Shall be executed multiple times until a Discover
>>> + * SVIDs VDO is returned ending either with a SVID value of 0x0000 in
>>> + * the last part of the last VDO or with a VDO containing two SVIDs
>>> + * with values of 0x0000.
>>> + *
>>> + * However, some odd dockers support SVIDs less than 12 but without
>>> + * 0x0000 in the last VDO, so we need to break the Discover SVIDs
>>> + * request and return false here.
>>> + */
>>> + return cnt == 7;
>>> tcpm_log(port, "SVID_DISCOVERY_MAX(%d) too low!", SVID_DISCOVERY_MAX);
>>> return false;
>> This is OK by men, but let's wait for Guenter.
> What ever happened to this patch?
It got lost in space.
Reviewed-by: Guenter Roeck <linux at roeck-us.net>
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