Re: [PATCH v4 09/33] gpu: nova-core: Hopper/Blackwell: skip GFW boot waiting

[John Hubbard]

On 2/11/26 2:09 AM, Danilo Krummrich wrote:
> On Tue Feb 10, 2026 at 3:45 AM CET, John Hubbard wrote:
...
>> diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
>> index 24feb0e8723e..f04e2a795e90 100644
>> --- a/drivers/gpu/nova-core/gpu.rs
>> +++ b/drivers/gpu/nova-core/gpu.rs
>> @@ -304,10 +304,19 @@ pub(crate) fn new<'a>(
>>          let chipset = spec.chipset();
>>  
>>          try_pin_init!(Self {
>> -            // We must wait for GFW_BOOT completion before doing any 
>> significant setup on the GPU.
>> +            // Turing, Ampere, Ada: we must wait for GFW_BOOT completion 
>> before doing any
>> +            // significant setup on the GPU.
>> +            //
>> +            // Hopper/Blackwell: skip GFW_BOOT completion waiting entirely, 
>> and use the simpler FSP
>> +            // Chain of Trust boot path (elsewhere) instead.
>>              _: {
>> -                gfw::wait_gfw_boot_completion(bar)
>> -                    .inspect_err(|_| dev_err!(pdev, "GFW boot did not 
>> complete\n"))?;
>> +                if matches!(
>> +                    chipset.arch(),
>> +                    Architecture::Turing | Architecture::Ampere | 
>> Architecture::Ada
> 
> I assume Blackwell is not an exception and we expect this to be the case for
> future architectures as well? I.e. checking for "!Architecture::Blackwell" 
> makes
> no sense?

You are correct. I've applied this locally, so that future GPUs
continue to skip GFW_BOOT (which I'm thinking of renaming now, but
in a future patchset):

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index f04e2a795e90..2034c05c04de 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -167,6 +167,18 @@ pub(crate) const fn dma_mask(&self) -> DmaMask {
             Self::Hopper | Self::Blackwell => DmaMask::new::<52>(),
         }
     }
+
+    /// Returns whether the GPU uses GFW_BOOT for firmware loading.
+    ///
+    /// Pre-Hopper architectures (Turing, Ampere, Ada) require waiting for 
GFW_BOOT completion
+    /// before any significant GPU setup. Hopper and later use the FSP Chain 
of Trust boot path
+    /// instead.
+    pub(crate) const fn needs_gfw_boot(&self) -> bool {
+        match self {
+            Self::Turing | Self::Ampere | Self::Ada => true,
+            _ => false,
+        }
+    }
 }
 
 impl TryFrom<u8> for Architecture {
@@ -304,16 +316,8 @@ pub(crate) fn new<'a>(
         let chipset = spec.chipset();
 
         try_pin_init!(Self {
-            // Turing, Ampere, Ada: we must wait for GFW_BOOT completion 
before doing any
-            // significant setup on the GPU.
-            //
-            // Hopper/Blackwell: skip GFW_BOOT completion waiting entirely, 
and use the simpler FSP
-            // Chain of Trust boot path (elsewhere) instead.
             _: {
-                if matches!(
-                    chipset.arch(),
-                    Architecture::Turing | Architecture::Ampere | 
Architecture::Ada
-                ) {
+                if chipset.arch().needs_gfw_boot() {
                     gfw::wait_gfw_boot_completion(bar)
                         .inspect_err(|_| dev_err!(pdev, "GFW boot did not 
complete\n"))?;
                 }


> 
>> +                ) {
>> +                    gfw::wait_gfw_boot_completion(bar)
>> +                        .inspect_err(|_| dev_err!(pdev, "GFW boot did not 
>> complete\n"))?;
>> +                }
>>              },

thanks,
-- 
John Hubbard