Re: [PATCH v2 04/13] drivers/ata: Stop using 32-bit MSR interfaces

[Jürgen Groß]

On 19.08.26 15:40, David Laight wrote:
> On Wed, 19 Aug 2026 12:23:05 +0200
> Juergen Gross <jgross@xxxxxxxx> wrote:
>
> > The 32-bit MSR interfaces rdmsr() and wrmsr() are planned to be
> > removed. Use the related 64-bit variants instead.
> >
> > In drivers/ata/pata_cs5536.c don't redefine rdmsr() and wrmsr() as
> > empty macros for avoiding misuse, but guard the affected code via
> > a simple #ifdef.
> >
> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > ---
> > V2:
> > - avoid sign extension when using wrmsrq() (Sashiko bot)
> > ---
> >   drivers/ata/pata_cs5535.c | 20 ++++++++++----------
> >   drivers/ata/pata_cs5536.c | 17 ++++++++---------
> >   2 files changed, 18 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/ata/pata_cs5535.c b/drivers/ata/pata_cs5535.c
> > index d793fc441b46..e16c7f4c7c27 100644
> > --- a/drivers/ata/pata_cs5535.c
> > +++ b/drivers/ata/pata_cs5535.c
> > @@ -90,7 +90,7 @@ static void cs5535_set_piomode(struct ata_port *ap, struct ata_device *adev)
> >   	static const u16 pio_cmd_timings[5] = {
> >   		0xF7F4, 0x53F3, 0x13F1, 0x5131, 0x1131
> >   	};
> > -	u32 reg, __maybe_unused dummy;
> > +	u32 reg;
> >   	struct ata_device *pair = ata_dev_pair(adev);
> >   
> >   	int mode = adev->pio_mode - XFER_PIO_0;
> > @@ -102,16 +102,16 @@ static void cs5535_set_piomode(struct ata_port *ap, struct ata_device *adev)
> >   		cmdmode = min(mode, pairmode);
> >   		/* Write the other drive timing register if it changed */
> >   		if (cmdmode < pairmode)
> > -			wrmsr(ATAC_CH0D0_PIO + 2 * pair->devno,
> > -				pio_cmd_timings[cmdmode] << 16 | pio_timings[pairmode], 0);
> > +			wrmsrq(ATAC_CH0D0_PIO + 2 * pair->devno,
> > +				(u32)pio_cmd_timings[cmdmode] << 16 | pio_timings[pairmode]);
>
> That cast is horribly subtle.
> Perhaps change the array to be u32 and shift the values in the array initialiser?

I like this idea.

I'll send V3 for this patch only as a reply to V2 of this patch.


Juergen

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