Messages in this thread | | | Date | Fri, 4 Mar 2022 12:11:32 +0100 | Subject | Re: [BUG] mtd: cfi_cmdset_0002: write regression since v4.17-rc1 | From | Ahmad Fatoum <> |
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Hello Tokunori-san,
On 20.02.22 13:22, Tokunori Ikegami wrote: > Hi Ahmad-san, > > Could you please try the version 2 patch attached for the error case? > This version is to check the DQ true data 0xFF by chip_good().
I had a similar patch locally as well at first. I just tested yours and I can't reproduce the issue.
> But I am not sure if this works or not since the error is possible to be caused by Hi-Z 0xff on floating bus or etc.
That it works for me could be because of Hi-Z 0xff, which is why decided against it.
>>>>> What seems to work for me is checking if chip_good or chip_ready >>>>> and map_word is equal to 0xFF. I can't justify why this is ok though. >>>>> (Worst case bus is floating at this point of time and Hi-Z is read >>>>> as 0xff on CPU data lines...) >>>> Sorry I am not sure about this. >>>> I thought the chip_ready() itself is correct as implemented as the data sheet in the past. >>>> But it did not work correctly so changed to use chip_good() instead as it is also correct. >>> What exactly in the datasheet makes you believe chip_good is not appropriate? >> I just mentioned about the actual issue behaviors as not worked chip_good() on S29GL964N and not worked chip_ready() on MX29GL512FHT2I-11G before etc. >> Anyway let me recheck the data sheet details as just checked it again quickly but needed more investigation to understand. > > As far as I checked still both chip_good() and chip_ready() seem correct but still the root cause is unknown. > If as you mentioned the issue was cased by the DQ true data 0xFF I am not sure why the read work without any error after the write operation. > Also if the error was caused by the Hi-Z 0xff on floating bus as mentioned I am not sure why the read work without any error after the write operation with chip_ready(). > Sorry anyway the root cause is also unknown when the write operation was changed to use chip_good() instead of chip_ready().
I've be ok with v1 then. Restores working behavior for me and shouldn't break others.
Cheers and thanks again, Ahmad
> > Regards, > Ikegami > >> >> Regards, >> Ikegami >> >>> >>> Cheers, >>> Ahmad >>> >>>
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