Hi Pawel,
On 14/02/2020 21:55, Pawel Laszczak wrote:
Pawel Laszczak wrote:
Hi,
Hi,
Jayshri Pawar wrote:
This patch adds additional parameter alt to config_ep_by_speed function.
This additional parameter allows to improve this function and
find proper usb_ss_ep_comp_descriptor.
Problem has appeared during testing f_tcm (BOT/UAS) driver function.
f_tcm function for SS use array of headers for both BOT/UAS alternate
setting:
static struct usb_descriptor_header *uasp_ss_function_desc[] = {
(struct usb_descriptor_header *) &bot_intf_desc,
(struct usb_descriptor_header *) &bot_uasp_ss_bi_desc,
(struct usb_descriptor_header *) &bot_bi_ep_comp_desc,
(struct usb_descriptor_header *) &bot_uasp_ss_bo_desc,
(struct usb_descriptor_header *) &bot_bo_ep_comp_desc,
(struct usb_descriptor_header *) &uasp_intf_desc,
(struct usb_descriptor_header *) &bot_uasp_ss_bi_desc,
(struct usb_descriptor_header *) &uasp_bi_ep_comp_desc,
(struct usb_descriptor_header *) &uasp_bi_pipe_desc,
(struct usb_descriptor_header *) &bot_uasp_ss_bo_desc,
(struct usb_descriptor_header *) &uasp_bo_ep_comp_desc,
(struct usb_descriptor_header *) &uasp_bo_pipe_desc,
(struct usb_descriptor_header *) &uasp_ss_status_desc,
(struct usb_descriptor_header *) &uasp_status_in_ep_comp_desc,
(struct usb_descriptor_header *) &uasp_status_pipe_desc,
(struct usb_descriptor_header *) &uasp_ss_cmd_desc,
(struct usb_descriptor_header *) &uasp_cmd_comp_desc,
(struct usb_descriptor_header *) &uasp_cmd_pipe_desc,
NULL,
};
The first 5 descriptors are associated with BOT alternate setting,
and others are associated with UAS.
During handling UAS alternate setting f_tcm drivr invokes
config_ep_by_speed and this function sets incorrect companion endpoint
descriptor in usb_ep object.
Instead setting ep->comp_desc to uasp_bi_ep_comp_desc function in this
case set ep->comp_desc to bot_uasp_ss_bi_desc.
This is due to the fact that it search endpoint based on endpoint
address:
for_each_ep_desc(speed_desc, d_spd) {
chosen_desc = (struct usb_endpoint_descriptor *)*d_spd;
if (chosen_desc->bEndpoitAddress == _ep->address)
goto ep_found;
}
And in result it uses the descriptor from BOT alternate setting
instead UAS.
Finally, it causes that controller driver during enabling endpoints
detect that just enabled endpoint for bot.
Signed-off-by: Jayshri Pawar <jpawar@xxxxxxxxxxx>
Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
---
drivers/usb/gadget/composite.c | 46 ++++++++++++++------
drivers/usb/gadget/function/f_acm.c | 7 +--
drivers/usb/gadget/function/f_ecm.c | 7 +--
drivers/usb/gadget/function/f_eem.c | 4 +-
drivers/usb/gadget/function/f_fs.c | 3 +-
drivers/usb/gadget/function/f_hid.c | 4 +-
drivers/usb/gadget/function/f_loopback.c | 2 +-
drivers/usb/gadget/function/f_mass_storage.c | 5 ++-
drivers/usb/gadget/function/f_midi.c | 2 +-
drivers/usb/gadget/function/f_ncm.c | 7 +--
drivers/usb/gadget/function/f_obex.c | 4 +-
drivers/usb/gadget/function/f_phonet.c | 4 +-
drivers/usb/gadget/function/f_rndis.c | 7 +--
drivers/usb/gadget/function/f_serial.c | 4 +-
drivers/usb/gadget/function/f_sourcesink.c | 11 +++--
drivers/usb/gadget/function/f_subset.c | 4 +-
drivers/usb/gadget/function/f_tcm.c | 36 +++++++--------
drivers/usb/gadget/function/f_uac1_legacy.c | 2 +-
drivers/usb/gadget/function/f_uvc.c | 5 ++-
drivers/usb/gadget/function/u_audio.c | 4 +-
include/linux/usb/composite.h | 2 +-
21 files changed, 99 insertions(+), 71 deletions(-)
I think we should create a new function and keep the old
config_ep_by_speed() for default alt-setting (e.i. have
config_ep_by_speed calls the new function with default alt-setting 0).
This way, we can keep compatibility with old function drivers and
minimize changes. At least that's what we did.
I don't think we need the separate function.
If we set last parameter alt=0 then this function will work in the same way as old one.
I wasn't talking about that. This patch modifies the
config_ep_by_speed() parameters, which requires to make a change to
every function driver of the kernel, and all in a single patch. This
makes it difficult to backport this fix. The only function driver that
you really need this fix for is f_tcm because of the stream eps right?
You could just add a function like
int config_ep_by_speed_and_alt(struct usb_gadget *g, struct
usb_function *f, unsigned int alt, struct usb_ep *_ep);
Then redefine config_ep_by_speed() to use it
int config_ep_by_speed(struct usb_gadget *g,
struct usb_function *f,
struct usb_ep *_ep)
{
return config_ep_by_speed_and_alt(g, f, 0, _ep);
}
This way, 1) you can split this patch, 2) you only need to make a fix to
f_tcm, 3) this fix can be backported much easier.
Anyways, this is just a suggestion. It's up to the maintainers to decide.
Thanks for clarification, now I got it. In my opinion, both solution has pros and cons
1. Original patch.
cons: introduce many change in many files
pros: we have only single API function - simpler Gadget Subsystem API
2. using config_ep_by_speed_and_alt
cons: minimal impact to other files.
pros: introduce the new API function which in fact could be omitted.
I would vote for 2.
It's only my personal opinion :) .
Felipe and Greg what is you opinion ?
Best Regards,
Pawel
BR,
Thinh
--
cheers,
-roger
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