Re: [PATCH v1 2/4] drm/hyperv: Explicitly set subvendor and subdevice for pci match array

["Uwe Kleine-König (The Capable Hub)" <u.kleine-koenig@baylibre.com>]

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Hallo Thomas,

On Thu, Jul 02, 2026 at 08:43:32AM +0200, Thomas Zimmermann wrote:
> Am 01.07.26 um 19:05 schrieb Uwe Kleine-König (The Capable Hub):
> > .subvendor and .subdevice were set to 0 implicitly, so only devices with
> > these two values set to 0 in hardware can probe automatically. Make this
> > requirement explicit.
> > 
> > While touching this array item, also make use of the pci macro designed
> > for that case.
> > 
> > Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
> > ---
> >   drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> > index 2e75fb793495..e766d87b7a9d 100644
> > --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> > +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> > @@ -51,8 +51,8 @@ static void hv_drm_pci_remove(struct pci_dev *pdev)
> >   static const struct pci_device_id hv_drm_pci_tbl[] = {
> >   	{
> > -		.vendor = PCI_VENDOR_ID_MICROSOFT,
> > -		.device = PCI_DEVICE_ID_HYPERV_VIDEO,
> > +		PCI_VDEVICE_SUB(MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO,
> > +				0, 0),
> 
> IDK, but it looks like an oversight to me.  Setting the sub-fields to ANY
> seems like the better fix.

That was my initial reflex, too. However while writing the commit log
for that change I noticed that since commit d750785f305e ("Staging: hv:
fix hv_utils module to properly autoload") from 2010 (applied to
v2.6.35-rc4) the driver never worked for hardware with .subvendor != 0
or .subdevice != 0. I cannot believe that something like that is
discovered 16 years later by chance during a rework by someone who
didn't try to run that hardware. And if I understand correctly, this is
emulated hardware and so I guess used quite a lot.

Best regards
Uwe

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