Messages in this thread | | | From | Ahmad Fatoum <> | Subject | Re: [BUG] mtd: cfi_cmdset_0002: write regression since v4.17-rc1 | Date | Fri, 28 Jan 2022 13:55:55 +0100 |
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Hello Tokunori-san,
On 15.12.21 18:34, Tokunori Ikegami wrote: > Hi Ahmad-san,
Thanks for your reply (and Thorsten for the reminder) and sorry for the delay. I had a lot of backlog after my time off.
> Sorry for the regression issue by the change: dfeae1073583. > To make sure could you please try with the word write instead of the buffered writes?
The issue is still there with #define FORCE_WORD_WRITE 1:
jffs2: Write clean marker to block at 0x000a0000 failed: -5 MTD do_write_oneword_once(): software timeout
> FYI: There are some changes to disable the buffered writes as below. > 1. https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=target/linux/ar71xx/patches-4.9/411-mtd-cfi_cmdset_0002-force-word-write.patch;h=ddd69f17e1ac16e8fc3a694c56231fee1e2ef149;hb=fec8fe806963c96a6506c2aebc3572d3a11f285f > 2. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/mtd/chips/cfi_cmdset_0002.c?h=v5.16-rc5&id=7e4404113686868858a34210c28ae122e967aa64 > > Note: > Currently I am not able to investigate the issue on the product for the change before. > > By the way in the past I had investigated the similar issue on Buffalo WZR-HP-G300NH using the S29GL256N. > It was not able to find the root cause by the investigation since not required actually at that time. > Also actually the buffered writes were disabled on the OpenWrt firmware as the change [1] above. > But I am not sure the reason detail to disable the buffered writes on the OpenWrt firmware. > I thought the issue not caused by the change: dfeae1073583 since the issue happened without the change. > > So I am not sure why the above change [2] needed to disable the buffered writes on Buffalo WZR-HP-G300NH. > Probably seems needed to disable the buffered writes on the other firmware also but not OpenWrt firmware. > > Anyway there are difference with your regression issue as below. > 1. Flash device: S29GL064N (Your regression issue), S29GL256N (WZR-HP-G300NH) > 2. Regression issue: Yes (Your regression issue), No (WZR-HP-G300NH as I investigated before)
Doesn't seem to be a buffered write issue here though as the writes did work fine before dfeae1073583. Any other ideas?
Cheers, Ahmad
> > Regards, > Ikegami > > On 2021/12/14 16:23, Thorsten Leemhuis wrote: >> [TLDR: adding this regression to regzbot; most of this mail is compiled >> from a few templates paragraphs some of you might have seen already.] >> >> Hi, this is your Linux kernel regression tracker speaking. >> >> Top-posting for once, to make this easy accessible to everyone. >> >> Thanks for the report. >> >> Adding the regression mailing list to the list of recipients, as it >> should be in the loop for all regressions, as explained here: >> https://www.kernel.org/doc/html/latest/admin-guide/reporting-issues.html >> >> To be sure this issue doesn't fall through the cracks unnoticed, I'm >> adding it to regzbot, my Linux kernel regression tracking bot: >> >> #regzbot ^introduced dfeae1073583 >> #regzbot title mtd: cfi_cmdset_0002: flash write accesses on the >> hardware fail on a PowerPC MPC8313 to a 8-bit-parallel S29GL064N flash >> #regzbot ignore-activity >> >> Reminder: when fixing the issue, please add a 'Link:' tag with the URL >> to the report (the parent of this mail), then regzbot will automatically >> mark the regression as resolved once the fix lands in the appropriate >> tree. For more details about regzbot see footer. >> >> Sending this to everyone that got the initial report, to make all aware >> of the tracking. I also hope that messages like this motivate people to >> directly get at least the regression mailing list and ideally even >> regzbot involved when dealing with regressions, as messages like this >> wouldn't be needed then. >> >> Don't worry, I'll send further messages wrt to this regression just to >> the lists (with a tag in the subject so people can filter them away), as >> long as they are intended just for regzbot. With a bit of luck no such >> messages will be needed anyway. >> >> Ciao, Thorsten (wearing his 'Linux kernel regression tracker' hat). >> >> P.S.: As a Linux kernel regression tracker I'm getting a lot of reports >> on my table. I can only look briefly into most of them. Unfortunately >> therefore I sometimes will get things wrong or miss something important. >> I hope that's not the case here; if you think it is, don't hesitate to >> tell me about it in a public reply. That's in everyone's interest, as >> what I wrote above might be misleading to everyone reading this; any >> suggestion I gave thus might sent someone reading this down the wrong >> rabbit hole, which none of us wants. >> >> BTW, I have no personal interest in this issue, which is tracked using >> regzbot, my Linux kernel regression tracking bot >> (https://linux-regtracking.leemhuis.info/regzbot/). I'm only posting >> this mail to get things rolling again and hence don't need to be CC on >> all further activities wrt to this regression. >> >> On 13.12.21 14:24, Ahmad Fatoum wrote: >>> Hi, >>> >>> I've been investigating a breakage on a PowerPC MPC8313: The SoC is connected >>> via the "Enhanced Local Bus Controller" to a 8-bit-parallel S29GL064N flash, >>> which is represented as a memory-mapped cfi-flash. >>> >>> The regression began in v4.17-rc1 with >>> >>> dfeae1073583 ("mtd: cfi_cmdset_0002: Change write buffer to check correct value") >>> >>> and causes all flash write accesses on the hardware to fail. Example output >>> after v5.1-rc2[1]: >>> >>> root@host:~# mount -t jffs2 /dev/mtdblock0 /mnt >>> MTD do_write_buffer_wait(): software timeout, address:0x000c000b. >>> jffs2: Write clean marker to block at 0x000c0000 failed: -5 >>> >>> This issue still persists with v5.16-rc. Reverting aforementioned patch fixes >>> it, but I am still looking for a change that keeps both Tokunori's and my >>> hardware happy. >>> >>> What Tokunori's patch did is that it strengthened the success condition >>> for flash writes: >>> >>> - Prior to the patch, DQ polling was done until bits >>> stopped toggling. This was taken as an indicator that the write succeeded >>> and was reported up the stack. i.e. success condition is chip_ready() >>> >>> - After the patch, polling continues until the just written data is >>> actually read back, i.e. success condition is chip_good() >>> >>> This new condition never holds for me, when DQ stabilizes, it reads 0xFF, >>> never the just written data. The data is still written and can be read back >>> on subsequent reads, just not at that point of time in the poll loop. >>> >>> We haven't had write issues for the years predating that patch. As the >>> regression has been mainline for a while, I am wondering what about my setup >>> that makes it pop up here, but not elsewhere? >>> >>> I consulted the data sheet[2] and found Figure 27, which describes DQ polling >>> during embedded algorithms. DQ switches from status output to "True" (I assume >>> True == all bits set == 0xFF) until CS# is reasserted. >>> >>> I compared with another chip's datasheet, and it (Figure 8.4) doesn't describe >>> such an intermittent "True" state. In any case, the driver polls a few hundred >>> times, however, before giving up, so there should be enough CS# toggles. >>> >>> >>> Locally, I'll revert this patch for now. I think accepting 0xFF as a success >>> condition may be appropriate, but I don't yet have the rationale to back it up. >>> >>> I am investigating this some more, probably with a logic trace, but I wanted >>> to report this in case someone has pointers and in case other people run into >>> the same issue. >>> >>> >>> Cheers, >>> Ahmad >>> >>> [1] Prior to d9b8a67b3b95 ("mtd: cfi: fix deadloop in cfi_cmdset_0002.c do_write_buffer") >>> first included with v5.1-rc2, failing writes just hung indefinitely in kernel space. >>> That's fixed, but the writes still fail. >>> >>> [2]: 001-98525 Rev. *B, https://www.infineon.com/dgdl/Infineon-S29GL064N_S29GL032N_64_Mbit_32_Mbit_3_V_Page_Mode_MirrorBit_Flash-DataSheet-v03_00-EN.pdf?fileId=8ac78c8c7d0d8da4017d0ed556fd548b >>> >>> [3]: https://www.mouser.com/datasheet/2/268/SST39VF1601C-SST39VF1602C-16-Mbit-x16-Multi-Purpos-709008.pdf >>> Note that "true data" means valid data here, not all bits one. >>> >
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