QCLINUX: drm/msm: Auto-detect separate GPU KMS mode based on HW topology

[naala-qcom]

On platforms with multiple display subsystems, such as SA8775P, the GPU binds to the first display subsystem that probes. This implicit binding prevents subsequent display subsystems from probing successfully, breaking multi-display support.

Use the tristate separate_gpu_kms module parameter with the default value set to auto (-1). In auto mode, the driver selects the binding behavior based on the number of GPUs and display subsystems. This allows display subsystems to probe independently when required, while preserving the existing single-card behavior on simpler systems.

The separate_gpu_kms module parameter has the following semantics:

-1 (auto, default):
Select the binding mode based on hardware topology. If exactly one
GPU and one display subsystem are present, bind them together to
form a single DRM device. Otherwise, expose the GPU and display
subsystems as separate DRM devices.

0:
Always bind the GPU and display together to form a single DRM
device.

1:
Always expose the GPU and display subsystems as separate DRM
devices.

This ensures correct probing on multi-display platforms without affecting single-display, single-GPU systems.

CRs-Fixed: 4443714

[qcomlnxci]

Test jobs on 894abb6

• Job 67254 on lemans-evk
• Job 67256 on monaco-evk
• Job 67258 on qcs615-ride
• Job 67257 on qcs6490-rb3gen2
• Job 67253 on qcs8300-ride
• Job 67255 on qcs9100-ride-r3
• Job 67252 on sm8750-mtp

[qcomlnxci]

Test Matrix

Test Case	lemans-evk	monaco-evk	qcs615-ride	qcs6490-rb3gen2	qcs8300-ride	qcs9100-ride-r3	sm8750-mtp
0_qcom-next-ci-premerge-tests	◻️	◻️	◻️	◻️	◻️	◻️	❌ Fail
BT_FW_KMD_Service	❌ Fail	❌ Fail	✅ Pass	◻️	✅ Pass	✅ Pass	❌ Fail
BT_ON_OFF	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	⚠️ skip
BT_SCAN	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	◻️
CPUFreq_Validation	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
CPU_affinity	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
DSP_AudioPD	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	◻️
Ethernet	⚠️ skip	⚠️ skip	⚠️ skip	◻️	✅ Pass	⚠️ skip	⚠️ skip
Freq_Scaling	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	❌ Fail
GIC	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
IPA	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
Interrupts	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
OpenCV	⚠️ skip	⚠️ skip	⚠️ skip	◻️	⚠️ skip	⚠️ skip	◻️
PCIe	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
Probe_Failure_Check	❌ Fail	❌ Fail	✅ Pass	◻️	✅ Pass	❌ Fail	❌ Fail
RMNET	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
UFS_Validation	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
USBHost	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	❌ Fail
WiFi_Firmware_Driver	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	◻️
WiFi_OnOff	✅ Pass	⚠️ skip	✅ Pass	◻️	✅ Pass	✅ Pass	◻️
cdsp_remoteproc	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	❌ Fail
hotplug	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
irq	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
kaslr	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
pinctrl	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
qcom_hwrng	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	◻️
remoteproc	✅ Pass	❌ Fail	✅ Pass	◻️	❌ Fail	✅ Pass	❌ Fail
rngtest	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	❌ Fail
shmbridge	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
smmu	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass
watchdog	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	◻️
wpss_remoteproc	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass	✅ Pass	✅ Pass

[qcomlnxci]

Test jobs on 34d28b2

• Job 67326 on lemans-evk
• Job 67325 on monaco-evk
• Job 67323 on qcs615-ride
• Job 67324 on qcs6490-rb3gen2
• Job 67328 on qcs8300-ride
• Job 67322 on qcs9100-ride-r3
• Job 67327 on sm8750-mtp

[qcomlnxci]

Test Matrix

Test Case	lemans-evk	monaco-evk	qcs615-ride	qcs6490-rb3gen2	qcs8300-ride	qcs9100-ride-r3	sm8750-mtp
0_qcom-next-ci-premerge-tests	◻️	◻️	◻️	◻️	◻️	◻️	❌ Fail
BT_FW_KMD_Service	❌ Fail	❌ Fail	✅ Pass	✅ Pass	❌ Fail	◻️	❌ Fail
BT_ON_OFF	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	⚠️ skip
BT_SCAN	❌ Fail	❌ Fail	✅ Pass	✅ Pass	✅ Pass	◻️	◻️
CPUFreq_Validation	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
CPU_affinity	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
DSP_AudioPD	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	◻️
Ethernet	✅ Pass	✅ Pass	⚠️ skip	⚠️ skip	✅ Pass	◻️	⚠️ skip
Freq_Scaling	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	❌ Fail
GIC	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
IPA	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
Interrupts	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
OpenCV	⚠️ skip	⚠️ skip	⚠️ skip	⚠️ skip	⚠️ skip	◻️	◻️
PCIe	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
Probe_Failure_Check	❌ Fail	❌ Fail	✅ Pass	❌ Fail	✅ Pass	◻️	❌ Fail
RMNET	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
UFS_Validation	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
USBHost	✅ Pass	✅ Pass	✅ Pass	❌ Fail	✅ Pass	◻️	❌ Fail
WiFi_Firmware_Driver	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	◻️
WiFi_OnOff	✅ Pass	⚠️ skip	✅ Pass	✅ Pass	✅ Pass	◻️	◻️
cdsp_remoteproc	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	❌ Fail
hotplug	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
irq	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
kaslr	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
pinctrl	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
qcom_hwrng	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	◻️
remoteproc	✅ Pass	❌ Fail	✅ Pass	✅ Pass	❌ Fail	◻️	❌ Fail
rngtest	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass
shmbridge	❌ Fail	✅ Pass	✅ Pass	✅ Pass	❌ Fail	◻️	✅ Pass
smmu	✅ Pass	✅ Pass	✅ Pass	✅ Pass	❌ Fail	◻️	✅ Pass
watchdog	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	◻️
wpss_remoteproc	✅ Pass	✅ Pass	✅ Pass	✅ Pass	✅ Pass	◻️	✅ Pass