Messages in this thread | | | Subject | Re: [PATCH v1] usb:gadget: Fix issue with config_ep_by_speed function. | From | Roger Quadros <> | Date | Wed, 4 Mar 2020 11:29:41 +0200 |
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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@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. >>>> >>> 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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