On 29/12/2023 23:36, Larry Finger wrote: > On 12/29/23 14:51, Bitterblue Smith wrote: >> Currently rtl_usb performs register writes using the async >> usb_submit_urb() function. This appears to work fine for the RTL8192CU, >> but the RTL8192DU (soon to be supported by rtlwifi) has a problem: >> it transmits everything at the 1M rate in the 2.4 GHz band. (The 5 GHZ >> band is still untested.) >> >> With this patch, rtl_usb performs the register writes using the >> synchronous usb_control_msg() function, and the RTL8192DU works >> normally. The RTL8192CU still works. >> >> The vendor drivers use the async writes in only one function, >> rtl8192du_trigger_gpio_0 / rtl8192cu_trigger_gpio_0, which probably >> doesn't even run in real life. They use sync writes everywhere else. >> >> Signed-off-by: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx> >> --- >> >> Larry, do you remember why, back in 2011, you chose to implement the >> async writes? > > Bitterblue, > > That was code provided by Realtek from their USB group. I think they were in China, not Taiwan. At least the PCI and USB groups were in different countries. They provided the code, and I just cleaned it up. tested it, and submitted it. If the sync function works for the cu and du chips, go for it. > > Larry > Ahh, okay. I guess we'll never know why they did that.
