On 11/7/25 9:09 PM, Timur Tabi wrote:
> On Fri, 2025-11-07 at 20:39 -0800, John Hubbard wrote:
...
>> let boot0 = regs::NV_PMC_BOOT_0::read(bar);
>>
>> - Spec::try_from(boot0)
>> + if boot0.use_boot42_instead() {
>> + Spec::try_from(regs::NV_PMC_BOOT_42::read(bar))
>> + } else {
>> + Spec::try_from(boot0)
>> + }
>> }
>
> Spec::try_from(boot0) will always fail, because we can't generate a Spec from
> a pre-Turing GPU,
> so it seems weird that we have it as an else condition.
>
> I don't think the comment and the code aligns. The code implies that
> sometimes we'll be using
> boot0 to generate the Spec, but that isn't true. However, the comment makes
> it clear that we'll
> be using boot42 only.
Hmmm, yes, the new use_boot42_instead() logic means that most of the
boot0 logic should actually be deleted now. OK, so I can apply this
diff on top, and everything still works:
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 5650c115c613..6d17ad3cec40 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -194,22 +194,11 @@ fn new(bar: &Bar0) -> Result<Spec> {
if boot0.use_boot42_instead() {
Spec::try_from(regs::NV_PMC_BOOT_42::read(bar))
} else {
- Spec::try_from(boot0)
+ Err(ENOTSUPP)
}
}
}
-impl TryFrom<regs::NV_PMC_BOOT_0> for Spec {
- type Error = Error;
-
- fn try_from(boot0: regs::NV_PMC_BOOT_0) -> Result<Self> {
- Ok(Self {
- chipset: boot0.chipset()?,
- revision: boot0.revision(),
- })
- }
-}
-
impl TryFrom<regs::NV_PMC_BOOT_42> for Spec {
type Error = Error;
diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs
index 5d6397f6450a..018bee114a3f 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -56,31 +56,6 @@ pub(crate) fn use_boot42_instead(self) -> bool {
!self.older_than_fermi()
}
-
- /// Combines `architecture_0` and `architecture_1` to obtain the
architecture of the chip.
- pub(crate) fn architecture(self) -> Result<Architecture> {
- Architecture::try_from(
- self.architecture_0() | (self.architecture_1() <<
Self::ARCHITECTURE_0_RANGE.len()),
- )
- }
-
- /// Combines `architecture` and `implementation` to obtain a code unique
to the chipset.
- pub(crate) fn chipset(self) -> Result<Chipset> {
- self.architecture()
- .map(|arch| {
- ((arch as u32) << Self::IMPLEMENTATION_RANGE.len())
- | u32::from(self.implementation())
- })
- .and_then(Chipset::try_from)
- }
-
- /// Returns the revision information of the chip.
- pub(crate) fn revision(self) -> Revision {
- Revision {
- major: self.major_revision(),
- minor: self.minor_revision(),
- }
- }
}
register!(NV_PMC_BOOT_42 @ 0x00000a00, "Extended architecture information" {
thanks,
--
John Hubbard
