linux-kernel - Re: [PATCH] arm64: dts: ti: k3-am62a7-sk: Disable mmc Schmitt Trigger

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <1a91fd40-e814-4b4c-8914-d8f0c4768e07@ti.com>
Date: Wed, 14 Jan 2026 16:04:29 -0600
From: Judith Mendez <jm@...com>
To: Markus Schneider-Pargmann <msp@...libre.com>, Alexander Sverdlin
	<alexander.sverdlin@...il.com>
CC: Vishal Mahaveer <vishalm@...com>, Kevin Hilman <khilman@...libre.com>,
	Dhruva Gole <d-gole@...com>, Sebin Francis <sebin.francis@...com>, "Kendall
 Willis" <k-willis@...com>, Akashdeep Kaur <a-kaur@...com>,
	<linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>, "Conor
 Dooley" <conor+dt@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, "Rob
 Herring" <robh@...nel.org>, <linux-kernel@...r.kernel.org>, Nishanth Menon
	<nm@...com>, Vignesh Raghavendra <vigneshr@...com>, Tero Kristo
	<kristo@...nel.org>
Subject: Re: [PATCH] arm64: dts: ti: k3-am62a7-sk: Disable mmc Schmitt Trigger

Hi Markus,

On 1/14/26 3:16 AM, Markus Schneider-Pargmann wrote:
> Hi Judith,
> 
> On Tue Jan 13, 2026 at 1:29 AM CET, Judith Mendez wrote:
>> On 1/6/26 10:22 AM, Markus Schneider-Pargmann (TI.com) wrote:
>>> Remove Schmitt Trigger from mmc pins. With Schmitt Trigger enabled
>>> u-boot SPL is not able to read u-boot from mmc:
>>>
>>>       Trying to boot from MMC2
>>>       Error reading cluster
>>>       spl_load_image_fat: error reading image u-boot.img, err - -22
>>>       Error: -22
>>>       SPL: Unsupported Boot Device!
>>>       SPL: failed to boot from all boot devices
>>>       ### ERROR ### Please RESET the board ###
>>>
>>> I bisected this issue between u-boot v2025.10 and v2026.01 and found the
>>> devicetree merge to be the problem. At a closer look I found the
>>> k3-pinctrl.h changes. Disabling the Schmitt Trigger fixes the u-boot SPL
>>> failure to read from mmc.
>>
>> I have tested 4 AM62A SK boards and I cannot replicate the issue
>> you are seeing. I do not see an issue with Schmitt Trigger in U-boot
>> nor Linux /:
> 
> Thanks for testing.
> 
>> Can you please run a quick tap sweep on MMC1 and MMC0 interfaces like
>> so? https://gist.github.com/jmenti/f4a73a8323e44bf717c6d2c528c499ca
>>
>> This will give me an idea if whether we should be talking about
>> revisiting characterization with ST_ENA=1.
> 
> The patch was a bit broken, but I think I managed to apply it to
> v2026.01 as it was supposed to be. (master currently doesn't boot even
> SPL, I don't have time right now to debug that).

as Nishanth, mentioned, master is missing two patches [0][1]

> 
> I attached the boot log. It does boot with your patch. Also can this be
> an issue with different SD cards?

Something does not quite add up,

Can you try the following 2 commands?

# mmc dev 1
# md.w 0xfa0810c


[0] https://gist.github.com/jmenti/92da6526e366e3f5cf41911724886471
[1] https://gist.github.com/jmenti/8cf589d0302248ad26da37128f622e98

~ Judith