From 3f26745caeab48fa1facacb7aef58d10783a2dae Mon Sep 17 00:00:00 2001 From: Pavel Hofman Date: Mon, 6 Sep 2021 14:04:00 +0200 Subject: [PATCH] FROMLIST: usb: gadget: f_uac2: fixed EP-IN wMaxPacketSize Async feedback patches broke enumeration on Windows 10 previously fixed by commit 789ea77310f0 ("usb: gadget: f_uac2: always increase endpoint max_packet_size by one audio slot"). While the existing calculation for EP OUT capture for async mode yields size+1 frame due to uac2_opts->fb_max > 0, playback side lost the +1 feature. Therefore the +1 frame addition must be re-introduced for playback. Win10 enumerates the device only when both EP IN and EP OUT max packet sizes are (at least) +1 frame. Signed-off-by: Pavel Hofman Tested-by: Henrik Enquist Tested-by: Jack Pham Bug: 199044440 Link: https://lore.kernel.org/linux-usb/b11414f0-1783-192e-2b79-066dd4c814d0@ivitera.com/ Change-Id: I74994d717b0eb543104e3ed7b20ca06c7c584be9 Signed-off-by: Jack Pham --- drivers/usb/gadget/function/f_uac2.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c index c3f87fa6874a..4b506412e273 100644 --- a/drivers/usb/gadget/function/f_uac2.c +++ b/drivers/usb/gadget/function/f_uac2.c @@ -585,11 +585,17 @@ static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts, ssize = uac2_opts->c_ssize; } - if (!is_playback && (uac2_opts->c_sync == USB_ENDPOINT_SYNC_ASYNC)) + if (!is_playback && (uac2_opts->c_sync == USB_ENDPOINT_SYNC_ASYNC)) { + // Win10 requires max packet size + 1 frame srate = srate * (1000 + uac2_opts->fb_max) / 1000; - - max_size_bw = num_channels(chmask) * ssize * - DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))); + // updated srate is always bigger, therefore DIV_ROUND_UP always yields +1 + max_size_bw = num_channels(chmask) * ssize * + (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1)))); + } else { + // adding 1 frame provision for Win10 + max_size_bw = num_channels(chmask) * ssize * + (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))) + 1); + } ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_size_bw, max_size_ep));