John Hubbard
2025-Nov-15 01:09 UTC
[PATCH v9 4/4] gpu: nova-core: provide a clear error report for unsupported GPUs
Pass in a PCI device to Spec::new(), and provide a Display
implementation for boot42, in order to provide a clear, concise report
of what happened: the driver read NV_PMC_BOOT42, and found that the GPU
is not supported.
For very old GPUs (older than Fermi), the driver still returns ENOTSUPP,
but it does so without a driver-specific dmesg report. That is exactly
appropriate, because if such a GPU is installed, it can only be
supported by Nouveau. And if so, the user is not helped by additional
error messages from Nova.
Here's the full dmesg output for a Blackwell (not yet supported) GPU:
NovaCore 0000:01:00.0: Probe Nova Core GPU driver.
NovaCore 0000:01:00.0: Unsupported chipset: boot42 = 0x1b2a1000 (architecture
0x1b, implementation 0x2)
NovaCore 0000:01:00.0: probe with driver NovaCore failed with error -524
Cc: Alexandre Courbot <acourbot at nvidia.com>
Cc: Danilo Krummrich <dakr at kernel.org>
Cc: Timur Tabi <ttabi at nvidia.com>
Cc: Joel Fernandes <joelagnelf at nvidia.com>
Signed-off-by: John Hubbard <jhubbard at nvidia.com>
---
drivers/gpu/nova-core/gpu.rs | 9 ++++++---
drivers/gpu/nova-core/regs.rs | 18 ++++++++++++++++++
2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 8e04628ca3d9..2bbc084e2095 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -191,7 +191,7 @@ pub(crate) struct Spec {
}
impl Spec {
- fn new(bar: &Bar0) -> Result<Spec> {
+ fn new(dev: &device::Device, bar: &Bar0) -> Result<Spec> {
// Some brief notes about boot0 and boot42, in chronological order:
//
// NV04 through NV50:
@@ -216,7 +216,10 @@ fn new(bar: &Bar0) -> Result<Spec> {
return Err(ENODEV);
}
- Spec::try_from(regs::NV_PMC_BOOT_42::read(bar))
+ let boot42 = regs::NV_PMC_BOOT_42::read(bar);
+ Spec::try_from(boot42).inspect_err(|_| {
+ dev_err!(dev, "Unsupported chipset: {}\n", boot42);
+ })
}
}
@@ -268,7 +271,7 @@ pub(crate) fn new<'a>(
bar: &'a Bar0,
) -> impl PinInit<Self, Error> + 'a {
try_pin_init!(Self {
- spec: Spec::new(bar).inspect(|spec| {
+ spec: Spec::new(pdev.as_ref(), bar).inspect(|spec| {
dev_info!(pdev.as_ref(),"NVIDIA ({})\n", spec);
})?,
diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs
index c6e2e08c754b..a53b013f2eca 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -67,6 +67,24 @@ pub(crate) fn chipset(self) -> Result<Chipset> {
})
.and_then(Chipset::try_from)
}
+
+ /// Returns the raw architecture value from the register.
+ fn architecture_raw(self) -> u8 {
+ ((self.0 >> Self::ARCHITECTURE_RANGE.start()) & ((1 <<
Self::ARCHITECTURE_RANGE.len()) - 1))
+ as u8
+ }
+}
+
+impl kernel::fmt::Display for NV_PMC_BOOT_42 {
+ fn fmt(&self, f: &mut kernel::fmt::Formatter<'_>) ->
kernel::fmt::Result {
+ write!(
+ f,
+ "boot42 = 0x{:08x} (architecture 0x{:x}, implementation
0x{:x})",
+ self.0,
+ self.architecture_raw(),
+ self.implementation()
+ )
+ }
}
// PBUS
--
2.51.2
John Hubbard
2025-Nov-15 01:12 UTC
[PATCH v9 4/4] gpu: nova-core: provide a clear error report for unsupported GPUs
On 11/14/25 5:09 PM, John Hubbard wrote:> Pass in a PCI device to Spec::new(), and provide a Display > implementation for boot42, in order to provide a clear, concise report > of what happened: the driver read NV_PMC_BOOT42, and found that the GPU > is not supported. > > For very old GPUs (older than Fermi), the driver still returns ENOTSUPP,ENODEV, actually, now. thanks, -- John Hubbard> but it does so without a driver-specific dmesg report. That is exactly > appropriate, because if such a GPU is installed, it can only be > supported by Nouveau. And if so, the user is not helped by additional > error messages from Nova. > > Here's the full dmesg output for a Blackwell (not yet supported) GPU: > > NovaCore 0000:01:00.0: Probe Nova Core GPU driver. > NovaCore 0000:01:00.0: Unsupported chipset: boot42 = 0x1b2a1000 (architecture 0x1b, implementation 0x2) > NovaCore 0000:01:00.0: probe with driver NovaCore failed with error -524 > > Cc: Alexandre Courbot <acourbot at nvidia.com> > Cc: Danilo Krummrich <dakr at kernel.org> > Cc: Timur Tabi <ttabi at nvidia.com> > Cc: Joel Fernandes <joelagnelf at nvidia.com> > Signed-off-by: John Hubbard <jhubbard at nvidia.com> > --- > drivers/gpu/nova-core/gpu.rs | 9 ++++++--- > drivers/gpu/nova-core/regs.rs | 18 ++++++++++++++++++ > 2 files changed, 24 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs > index 8e04628ca3d9..2bbc084e2095 100644 > --- a/drivers/gpu/nova-core/gpu.rs > +++ b/drivers/gpu/nova-core/gpu.rs > @@ -191,7 +191,7 @@ pub(crate) struct Spec { > } > > impl Spec { > - fn new(bar: &Bar0) -> Result<Spec> { > + fn new(dev: &device::Device, bar: &Bar0) -> Result<Spec> { > // Some brief notes about boot0 and boot42, in chronological order: > // > // NV04 through NV50: > @@ -216,7 +216,10 @@ fn new(bar: &Bar0) -> Result<Spec> { > return Err(ENODEV); > } > > - Spec::try_from(regs::NV_PMC_BOOT_42::read(bar)) > + let boot42 = regs::NV_PMC_BOOT_42::read(bar); > + Spec::try_from(boot42).inspect_err(|_| { > + dev_err!(dev, "Unsupported chipset: {}\n", boot42); > + }) > } > } > > @@ -268,7 +271,7 @@ pub(crate) fn new<'a>( > bar: &'a Bar0, > ) -> impl PinInit<Self, Error> + 'a { > try_pin_init!(Self { > - spec: Spec::new(bar).inspect(|spec| { > + spec: Spec::new(pdev.as_ref(), bar).inspect(|spec| { > dev_info!(pdev.as_ref(),"NVIDIA ({})\n", spec); > })?, > > diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs > index c6e2e08c754b..a53b013f2eca 100644 > --- a/drivers/gpu/nova-core/regs.rs > +++ b/drivers/gpu/nova-core/regs.rs > @@ -67,6 +67,24 @@ pub(crate) fn chipset(self) -> Result<Chipset> { > }) > .and_then(Chipset::try_from) > } > + > + /// Returns the raw architecture value from the register. > + fn architecture_raw(self) -> u8 { > + ((self.0 >> Self::ARCHITECTURE_RANGE.start()) & ((1 << Self::ARCHITECTURE_RANGE.len()) - 1)) > + as u8 > + } > +} > + > +impl kernel::fmt::Display for NV_PMC_BOOT_42 { > + fn fmt(&self, f: &mut kernel::fmt::Formatter<'_>) -> kernel::fmt::Result { > + write!( > + f, > + "boot42 = 0x{:08x} (architecture 0x{:x}, implementation 0x{:x})", > + self.0, > + self.architecture_raw(), > + self.implementation() > + ) > + } > } > > // PBUS