Re: [PATCH wireless v1] wifi: rtw88: sdio: Always use two consecutive bytes for word operations

[Kalle Valo]

Ping-Ke Shih <pkshih@xxxxxxxxxxx> writes:

>> -----Original Message-----
>> From: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
>> Sent: Monday, May 15, 2023 4:04 AM
>> To: linux-wireless@xxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx; Ping-Ke Shih <pkshih@xxxxxxxxxxx>; tony0620emma@xxxxxxxxx;
>> kvalo@xxxxxxxxxx; Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>; Larry Finger
>> <Larry.Finger@xxxxxxxxxxxx>; Rudi Heitbaum <rudi@xxxxxxxxxxxx>
>> Subject: [PATCH wireless v1] wifi: rtw88: sdio: Always use two consecutive bytes for word operations
>> 
>> The Allwinner sunxi-mmc controller cannot handle word (16 bit)
>> transfers. So and sdio_{read,write}w fails with messages like the
>> following example using an RTL8822BS (but the same problems were also
>> observed with RTL8822CS and RTL8723DS chips):
>>   rtw_8822bs mmc1:0001:1: Firmware version 27.2.0, H2C version 13
>>   sunxi-mmc 4021000.mmc: unaligned scatterlist: os f80 length 2
>>   sunxi-mmc 4021000.mmc: map DMA failed
>>   rtw_8822bs mmc1:0001:1: sdio read16 failed (0x10230): -22
>> 
>> Use two consecutive single byte accesses for word operations instead. It
>> turns out that upon closer inspection this is also what the vendor
>> driver does, even though it does have support for sdio_{read,write}w. So
>> we can conclude that the rtw88 chips do support word access but only on
>> SDIO controllers that also support it. Since there's no way to detect if
>> the controller supports word access or not the rtw88 sdio driver
>> switches to the easiest approach: avoiding word access.
>> 
>> Reported-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
>> Closes: https://lore.kernel.org/linux-wireless/527585e5-9cdd-66ed-c3af-6da162f4b720@xxxxxxxxxxxx/
>
> "Closes:" seems not a regular tag. Use "Link: " instead.

Actually the documentation now talks about Closes tag:

https://docs.kernel.org/process/5.Posting.html#patch-formatting-and-changelogs

I guess this tag is a recent addition?

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