Hi Pavel, On 10/11/2019 9:54 AM, Minas Harutyunyan wrote: > 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 > <linux-usb@vger.kernel.org>. 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 > Could you please send regdump and debug log for failing case.
Thanks, Minas
