Re: FAILED: patch "[PATCH] mtd: spi-nor: sst: Fix write enable before AAI sequence" failed to apply to 6.6-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, May 07, 2026 at 07:31:43PM +0200, Hendrik Donner wrote:
> Hello,
> 
> On 5/4/26 10:38, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 6.6-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > To reproduce the conflict and resubmit, you may use the following commands:
> > 
> > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
> > git checkout FETCH_HEAD
> > git cherry-pick -x a0f64241d3566a49c0a9b33ba7ae458ae22003a9
> > # <resolve conflicts, build, test, etc.>
> > git commit -s
> > git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026050405-manly-surplus-9d27@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
> > 
> > Possible dependencies:
> > 
> > 
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------ original commit in Linus's tree ------------------
> > 
> >  From a0f64241d3566a49c0a9b33ba7ae458ae22003a9 Mon Sep 17 00:00:00 2001
> > From: Sanjaikumar V S <sanjaikumar.vs@dicortech.com>
> > Date: Wed, 11 Mar 2026 10:30:56 +0000
> > Subject: [PATCH] mtd: spi-nor: sst: Fix write enable before AAI sequence
> > 
> > When writing to SST flash starting at an odd address, a single byte is
> > first programmed using the byte program (BP) command. After this
> > operation completes, the flash hardware automatically clears the Write
> > Enable Latch (WEL) bit.
> > 
> > If an AAI (Auto Address Increment) word program sequence follows, it
> > requires WEL to be set. Without re-enabling writes, the AAI sequence
> > fails.
> > 
> > Add spi_nor_write_enable() after the odd-address byte program when more
> > data needs to be written. Use a local boolean for clarity.
> > 
> > Fixes: b199489d37b2 ("mtd: spi-nor: add the framework for SPI NOR")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Sanjaikumar V S <sanjaikumar.vs@dicortech.com>
> > Tested-by: Hendrik Donner <hd@os-cillation.de>
> > Reviewed-by: Hendrik Donner <hd@os-cillation.de>
> > Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
> > 
> > diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c
> > index 175211fe6a5e..db02c14ba16f 100644
> > --- a/drivers/mtd/spi-nor/sst.c
> > +++ b/drivers/mtd/spi-nor/sst.c
> > @@ -203,6 +203,8 @@ static int sst_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
> >   	/* Start write from odd address. */
> >   	if (to % 2) {
> > +		bool needs_write_enable = (len > 1);
> > +
> >   		/* write one byte. */
> >   		ret = sst_nor_write_data(nor, to, 1, buf);
> >   		if (ret < 0)
> > @@ -210,6 +212,17 @@ static int sst_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
> >   		to++;
> >   		actual++;
> > +
> > +		/*
> > +		 * Byte program clears the write enable latch. If more
> > +		 * data needs to be written using the AAI sequence,
> > +		 * re-enable writes.
> > +		 */
> > +		if (needs_write_enable) {
> > +			ret = spi_nor_write_enable(nor);
> > +			if (ret)
> > +				goto out;
> > +		}
> >   	}
> >   	/* Write out most of the data here. */
> > 
> 
> it doesn't apply because of changes made in
> 18bcb4aa54eab75dce41e5c176a1c2bff94f0f79.
> 
> That commit was never backported and is not in any stable tree older
> than 6.12.y. So it needs to be applied first to 5.10.y, 5.15.y, 6.1.y
> and 6.6.y. It's a refactor commit that should not change behaviour at all.

The refactor commit worked for 6.1.y and 6.6.y, but not the others.

thanks,

greg k-h