Hi Pavel, On 10/10/2019 8:36 PM, Pavel Hofman wrote: > I forgot version information - branch 5.3 > https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_raspberrypi_linux_tree_rpi-2D5.3.y_drivers_usb_dwc2&d=DwICBA&c=DPL6_X_6JkXFx7AXWqB0tg&r=cQBKt4q-qzNVC53rNAwuwplH23V61rHQhhULvdLA0U8&m=roVTrb8UpajEEelBpJicBEnDNjj4_Ee8-BPoSHmYa-8&s=6Ijfw31Oy-ep8P8YzooBpOpciF5CLCBeGj7iYuXzQMQ&e= > > with latest version of > https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_torvalds_linux_blob_master_drivers_usb_dwc2_gadget.c&d=DwICBA&c=DPL6_X_6JkXFx7AXWqB0tg&r=cQBKt4q-qzNVC53rNAwuwplH23V61rHQhhULvdLA0U8&m=roVTrb8UpajEEelBpJicBEnDNjj4_Ee8-BPoSHmYa-8&s=eEEdIx-XNzSx7PzLmt5XYWeoRfeqyI1W5aZLt2GNSok&e= > > (i.e. only a few patches behind upstream master). > > Dne 10. 10. 19 v 18:33 Pavel Hofman napsal(a): >> Dear Mr. Harutyunyan, >> >> I am turning to you as the core developer of the dwc2 driver in linux. >> I would like to ask you for help with debugging the following issue: >> >> I would like to improve the g_audio gadget for RaspberryPi4 (the >> gadget alsa device stalls when no USB communication occurs + a few >> other issues but this is not important now). >> >> EP IN works perfectly, I could pass audio 768kHz/3 bytes/3 channels >> which is the maximum for one endpoint (768/8 * 3 * 3 = 864 bytes every >> 125us frame) >> >> But for EP OUT, every g_audio configuration creating USB packet size > >> 900 bytes (approx) results in dwc2/gadget.c not passing any data to >> the audio function (req->actual is always zero). >> >> For interval=8 (bInterval = 4, i.e. data every 1ms): >> >> * 32kHz/1byte/28 channels = 896 bytes packet size -> working perfect, >> bitperfect transmission >> >> * 32kHz/1byte/29 channels = 928 bytes packet size -> no data passed to >> g_audio.c (dwc2_hsotg_handle_outdone() is never called in >> dwc2_hsotg_epint() >> https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_torvalds_linux_blob_master_drivers_usb_dwc2_gadget.c-23L3039&d=DwICBA&c=DPL6_X_6JkXFx7AXWqB0tg&r=cQBKt4q-qzNVC53rNAwuwplH23V61rHQhhULvdLA0U8&m=roVTrb8UpajEEelBpJicBEnDNjj4_Ee8-BPoSHmYa-8&s=wMRtUtO5zFAK062HmVWxGAVxbpX9h9wlpzJaQU_URkg&e= >> >> ) >> >> I tried for different packet sizes, every setup below 900 bytes works, >> every setup above 900 bytes does not work. >> >> Tested with host x86 linux PC and USB loopback on the same RPi (from >> the other USB onboard controller), exactly same behavior for both hosts. >> >> It looks as if the DWC2 considers all isochronous packets with size > >> 900 bytes as incomplete. I do not have a hardware USB analyzer, but >> wireshark on the host PC shows the packets are properly passed to the >> USB controller in linux. >> >> >> I found a DWC2 datasheet at >> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.intel.com_content_www_us_en_programmable_documentation_sfo1410144425160.html&d=DwICBA&c=DPL6_X_6JkXFx7AXWqB0tg&r=cQBKt4q-qzNVC53rNAwuwplH23V61rHQhhULvdLA0U8&m=roVTrb8UpajEEelBpJicBEnDNjj4_Ee8-BPoSHmYa-8&s=bHXds7A-CT3K5jg2C8JX8Gvcl2Yy-ojtuLM5Z4AkrFc&e= >> >> . >> >> I can provide any debugging information, debugfs of the dwc2 module, >> kernel dynamic debug traces etc. >> >> RPi4 would make a great audio device if the gadget mode worked >> reliably. I can fix/code the alsa device issues, but USB core is above >> my skills. >> >> Thank you very much in advance. >> >> Best regards, >> >> Pavel Hofman.
First of all I'll prefer communicate via Linux-usb mailing list <email@example.com>. Let's keep this mailing list address in CC. And one more thing, keep on the beginning of subject follow string: "usb: dwc2: " Thank you for your email. I'll dedicate time on the next week to debug your case. Thanks, Minas