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SubjectRe: [PATCH v1] usb:gadget: Fix issue with config_ep_by_speed function.
Date
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@cadence.com>
> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
> ---
> 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.

BR,
Thinh
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