Re: [PATCH v4 2/2] usb: musb: gadget: don't flush a waiting RX packet when queueing a request

[sashiko-bot@kernel.org]

> Since commit 3fc137386c46 ("usb: musb: Fix hardware lockup on first Rx
> endpoint request"), musb_ep_restart() flushes the RX FIFO instead of
> calling rxstate(), with the premise that in case of Ethernet, dropping
> a couple of packets during gadget initialization is not an issue,
> because it will only happen when the software is not yet ready.
> 
> But when using other functions with musb, for example, f_mass_storage
> or f_acm, this code path will be used not only when the software is not
> yet ready, but also mid-communication, and it will cause data loss.
> Data loss happens on gadgets that don't always have requests queued
> for an ep.
> 
> The timeline of a data loss:
> 
> 1. A function that does not have a lot of requests pre-queued
> [ ... ]
> This patch was also tested with suspend to RAM on the Pine A64+,
> both idle and during a transfer.
> 
> Fixes: 3fc137386c46 ("usb: musb: Fix hardware lockup on first Rx endpoint request")
> Signed-off-by: Elvira Khabirova <lineprinter0@gmail.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261107221904.82487-1-lineprinter0@gmail.com?part=2