From: Mika Westerberg mika.westerberg@linux.intel.com
[ Upstream commit f7e37affbc9085f2b77ccb6596521a44eabf7505 ]
Add Intel Wildcat Lake SPI serial flash PCI ID to the list of supported devices.
Signed-off-by: Mika Westerberg mika.westerberg@linux.intel.com Link: https://patch.msgid.link/20251020145415.3377022-4-mika.westerberg@linux.inte... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
## BACKPORT ANALYSIS COMPLETE
**Backport Status: YES**
---
## DETAILED ANALYSIS
### 1. COMMIT CHARACTERIZATION
**Type**: Hardware enablement (PCI device ID addition)
**Code Changes**: - Single line addition to `drivers/spi/spi-intel-pci.c` - Adds PCI device ID `0x4d23` (Intel Wildcat Lake SPI serial flash) - Maps to existing `cnl_info` configuration structure - No behavioral changes to existing code paths
### 2. SEMANTIC CODE ANALYSIS FINDINGS
#### Tools Used: - **Read**: Examined the complete file structure (drivers/spi/spi-intel- pci.c:68-99) - **Grep**: Located PCI device table usage and MODULE_DEVICE_TABLE macro - **Git analysis**: Reviewed commit history and backport precedents
#### Impact Scope Analysis: - **Direct impact**: Only affects systems with PCI ID 0x4d23 (Wildcat Lake hardware) - **Caller analysis**: The PCI device table is used by the kernel's PCI subsystem for automatic device-driver matching - **Dependency analysis**: Uses `cnl_info` structure (drivers/spi/spi- intel-pci.c:38-41), which has existed since 2022 - **Risk assessment**: Zero risk to existing hardware - new entry only triggers on matching PCI ID
### 3. BACKPORT PRECEDENT (Strong Evidence)
I found multiple similar commits that **WERE backported** to stable trees:
**Example 1 - Lunar Lake-M** (commit ec33549be99fe): ``` commit ec33549be99fe25c6927c8b3d6ed13918b27656e Author: Mika Westerberg mika.westerberg@linux.intel.com Commit: Sasha Levin sashal@kernel.org [STABLE MAINTAINER]
spi: intel-pci: Add support for Lunar Lake-M SPI serial flash
[ Upstream commit 8f44e3808200c1434c26ef459722f88f48b306df ] ```
**Example 2 - Granite Rapids** (commit 60446b5e74865): ``` commit 60446b5e74865acff1af5f2d89d99551c8e6e2c1 Author: Mika Westerberg mika.westerberg@linux.intel.com Commit: Greg Kroah-Hartman gregkh@linuxfoundation.org [STABLE MAINTAINER]
spi: intel-pci: Add support for Granite Rapids SPI serial flash
[ Upstream commit 9855d60cfc720ff32355484c119acafd3c4dc806 ] ```
**Key Finding**: Both commits were backported to stable trees by stable maintainers (Sasha Levin, Greg Kroah-Hartman) **despite having NO explicit stable tags** in the original commits.
### 4. STABLE TREE COMPLIANCE
**Positive Factors**: - ✅ Fixes a real user problem (Wildcat Lake users cannot access SPI flash on stable kernels) - ✅ Extremely low risk (single line, static table entry) - ✅ No architectural changes - ✅ No dependencies on unreleased features - ✅ Follows established backporting pattern for PCI ID additions - ✅ "Obviously correct" - uses tested configuration from 20+ other Intel platforms
**Considerations**: - ⚠️ Technically a "new feature" (new hardware support) - ✅ However, PCI ID additions are a **special exception** routinely accepted by stable maintainers - ✅ Hardware enablement is considered "fixing" missing support for existing hardware
### 5. DEPENDENCY VERIFICATION
- **cnl_info structure**: Present since 2022, exists in all stable kernels that would receive this backport - **PCI_VDEVICE macro**: Standard kernel infrastructure - **intel_spi_probe()**: Core function, no recent changes that would conflict - **Clean backport**: No conflicts expected with any stable kernel version
### 6. RISK ANALYSIS
**Regression Risk**: **MINIMAL** - Only triggered when PCI ID 0x4d23 is detected - No effect on systems without Wildcat Lake hardware - Uses well-tested code path (cnl_info shared with 20+ other platforms) - No user-space API changes
**Testing Coverage**: - Same code path used by numerous Intel platforms (Ice Lake, Tiger Lake, Alder Lake, etc.) - Configuration structure (cnl_info) battle-tested across multiple generations
### 7. COMMIT MESSAGE ANALYSIS
The commit message is: - ✅ Clear and descriptive - ✅ Identifies specific hardware (Intel Wildcat Lake) - ✅ Consistent with previous similar commits - ❌ No "Fixes:" tag (not applicable - this is new hardware support) - ❌ No "Cc: stable@vger.kernel.org" tag (but precedent shows this doesn't prevent backporting)
---
## RECOMMENDATION
**YES - This commit SHOULD be backported to stable kernel trees**
### Rationale:
1. **Strong precedent**: Multiple similar PCI ID additions for Intel platforms (Lunar Lake, Granite Rapids, Arrow Lake) have been backported to stable trees by stable maintainers
2. **User benefit**: Enables critical SPI flash functionality for Wildcat Lake hardware owners running stable kernels
3. **Minimal risk**: Single-line change to static table with no impact on existing hardware
4. **Well-established pattern**: PCI ID additions for hardware enablement are routinely accepted for stable backports as they "fix" missing hardware support
5. **Clean backport**: No dependencies or conflicts expected
### Target Stable Trees: - All currently maintained stable kernels (6.17.x, 6.16.x, 6.15.x, etc.) - The commit is from v6.18-rc3, so it would benefit users on any stable kernel before 6.18
drivers/spi/spi-intel-pci.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/spi/spi-intel-pci.c b/drivers/spi/spi-intel-pci.c index 4b63cb98df9cc..4bb158a23349e 100644 --- a/drivers/spi/spi-intel-pci.c +++ b/drivers/spi/spi-intel-pci.c @@ -75,6 +75,7 @@ static const struct pci_device_id intel_spi_pci_ids[] = { { PCI_VDEVICE(INTEL, 0x38a4), (unsigned long)&bxt_info }, { PCI_VDEVICE(INTEL, 0x43a4), (unsigned long)&cnl_info }, { PCI_VDEVICE(INTEL, 0x4b24), (unsigned long)&bxt_info }, + { PCI_VDEVICE(INTEL, 0x4d23), (unsigned long)&cnl_info }, { PCI_VDEVICE(INTEL, 0x4da4), (unsigned long)&bxt_info }, { PCI_VDEVICE(INTEL, 0x51a4), (unsigned long)&cnl_info }, { PCI_VDEVICE(INTEL, 0x54a4), (unsigned long)&cnl_info },