Re: [PATCH v3 25/25] drm/xe: Add modparam to enable / disable ULLS on migrate queue

[Matthew Brost <matthew.brost@intel.com>]

On Thu, Mar 05, 2026 at 03:59:24PM -0700, Summers, Stuart wrote:
> On Fri, 2026-02-27 at 17:35 -0800, Matthew Brost wrote:
> > Having modparam to enable / disable ULLS on migrate queue will help
> > with
> > quick experiments.
> 
> Can we do this in configfs instead?
> 

We could... I don't know about the guidance rules on configfs though -
e.g., is that ABI? Modparams definitely are not... I don't really want
anything to be ABI here - I'd rather just drop this than add ABI.

Matt

> Thanks,
> Stuart
> 
> > 
> > Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_debugfs.c      |  1 +
> >  drivers/gpu/drm/xe/xe_defaults.h     |  1 +
> >  drivers/gpu/drm/xe/xe_device.c       | 12 +++++++++---
> >  drivers/gpu/drm/xe/xe_device_types.h |  5 +++++
> >  drivers/gpu/drm/xe/xe_migrate.c      |  2 +-
> >  drivers/gpu/drm/xe/xe_module.c       |  4 ++++
> >  drivers/gpu/drm/xe/xe_module.h       |  1 +
> >  7 files changed, 22 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_debugfs.c
> > b/drivers/gpu/drm/xe/xe_debugfs.c
> > index 844cfafe1ec7..049389205b3f 100644
> > --- a/drivers/gpu/drm/xe/xe_debugfs.c
> > +++ b/drivers/gpu/drm/xe/xe_debugfs.c
> > @@ -85,6 +85,7 @@ static int info(struct seq_file *m, void *data)
> >         drm_printf(&p, "tile_count %d\n", xe->info.tile_count);
> >         drm_printf(&p, "vm_max_level %d\n", xe->info.vm_max_level);
> >         drm_printf(&p, "force_execlist %s\n", str_yes_no(xe-
> > >info.force_execlist));
> > +       drm_printf(&p, "ulls_enable %s\n", str_yes_no(xe-
> > >info.ulls_enable));
> >         drm_printf(&p, "has_flat_ccs %s\n", str_yes_no(xe-
> > >info.has_flat_ccs));
> >         drm_printf(&p, "has_usm %s\n", str_yes_no(xe->info.has_usm));
> >         drm_printf(&p, "skip_guc_pc %s\n", str_yes_no(xe-
> > >info.skip_guc_pc));
> > diff --git a/drivers/gpu/drm/xe/xe_defaults.h
> > b/drivers/gpu/drm/xe/xe_defaults.h
> > index c8ae1d5f3d60..299360546283 100644
> > --- a/drivers/gpu/drm/xe/xe_defaults.h
> > +++ b/drivers/gpu/drm/xe/xe_defaults.h
> > @@ -14,6 +14,7 @@
> >  #endif
> >  
> >  #define
> > XE_DEFAULT_PROBE_DISPLAY               IS_ENABLED(CONFIG_DRM_XE_DISPL
> > AY)
> > +#define XE_DEFAULT_ULLS_ENABLE                 true
> >  #define XE_DEFAULT_VRAM_BAR_SIZE               0
> >  #define
> > XE_DEFAULT_FORCE_PROBE                 CONFIG_DRM_XE_FORCE_PROBE
> >  #define XE_DEFAULT_MAX_VFS                     ~0
> > diff --git a/drivers/gpu/drm/xe/xe_device.c
> > b/drivers/gpu/drm/xe/xe_device.c
> > index b7ad7f97e68c..18af003c95c5 100644
> > --- a/drivers/gpu/drm/xe/xe_device.c
> > +++ b/drivers/gpu/drm/xe/xe_device.c
> > @@ -437,6 +437,14 @@ static void xe_device_destroy(struct drm_device
> > *dev, void *dummy)
> >         ttm_device_fini(&xe->ttm);
> >  }
> >  
> > +static void xe_device_parse_modparam(struct xe_device *xe)
> > +{
> > +       xe->info.force_execlist = xe_modparam.force_execlist;
> > +       xe->info.ulls_enable = xe_modparam.ulls_enable;
> > +       xe->atomic_svm_timeslice_ms = 5;
> > +       xe->min_run_period_lr_ms = 5;
> > +}
> > +
> >  struct xe_device *xe_device_create(struct pci_dev *pdev,
> >                                    const struct pci_device_id *ent)
> >  {
> > @@ -470,9 +478,7 @@ struct xe_device *xe_device_create(struct pci_dev
> > *pdev,
> >  
> >         xe->info.devid = pdev->device;
> >         xe->info.revid = pdev->revision;
> > -       xe->info.force_execlist = xe_modparam.force_execlist;
> > -       xe->atomic_svm_timeslice_ms = 5;
> > -       xe->min_run_period_lr_ms = 5;
> > +       xe_device_parse_modparam(xe);
> >  
> >         err = xe_irq_init(xe);
> >         if (err)
> > diff --git a/drivers/gpu/drm/xe/xe_device_types.h
> > b/drivers/gpu/drm/xe/xe_device_types.h
> > index b3737dfcc45c..a20ff1707227 100644
> > --- a/drivers/gpu/drm/xe/xe_device_types.h
> > +++ b/drivers/gpu/drm/xe/xe_device_types.h
> > @@ -231,6 +231,11 @@ struct xe_device {
> >                 u8 skip_pcode:1;
> >                 /** @info.needs_shared_vf_gt_wq: needs shared GT WQ
> > on VF */
> >                 u8 needs_shared_vf_gt_wq:1;
> > +               /**
> > +                * @info.ulls_enable: Enable ULLS on migration queue
> > in LR VM
> > +                * open
> > +                */
> > +               u8 ulls_enable:1;
> >         } info;
> >  
> >         /** @wa_active: keep track of active workarounds */
> > diff --git a/drivers/gpu/drm/xe/xe_migrate.c
> > b/drivers/gpu/drm/xe/xe_migrate.c
> > index 62f27868f56b..9f02e238e7c6 100644
> > --- a/drivers/gpu/drm/xe/xe_migrate.c
> > +++ b/drivers/gpu/drm/xe/xe_migrate.c
> > @@ -447,7 +447,7 @@ void xe_migrate_ulls_enter(struct xe_migrate *m)
> >  
> >         xe_assert(xe, xe->info.has_usm);
> >  
> > -       if (!IS_DGFX(xe) || IS_SRIOV_VF(xe))
> > +       if (!IS_DGFX(xe) || IS_SRIOV_VF(xe) || !xe->info.ulls_enable)
> >                 return;
> >  
> >  job_alloc:
> > diff --git a/drivers/gpu/drm/xe/xe_module.c
> > b/drivers/gpu/drm/xe/xe_module.c
> > index 4cb578182912..bb4fb967aec9 100644
> > --- a/drivers/gpu/drm/xe/xe_module.c
> > +++ b/drivers/gpu/drm/xe/xe_module.c
> > @@ -22,6 +22,7 @@
> >  
> >  struct xe_modparam xe_modparam = {
> >         .probe_display =        XE_DEFAULT_PROBE_DISPLAY,
> > +       .ulls_enable =          XE_DEFAULT_ULLS_ENABLE,
> >         .guc_log_level =        XE_DEFAULT_GUC_LOG_LEVEL,
> >         .force_probe =          XE_DEFAULT_FORCE_PROBE,
> >  #ifdef CONFIG_PCI_IOV
> > @@ -45,6 +46,9 @@ MODULE_PARM_DESC(probe_display, "Probe display HW,
> > otherwise it's left untouched
> >                  "[default=" __stringify(XE_DEFAULT_PROBE_DISPLAY)
> > "])");
> >  #endif
> >  
> > +module_param_named(ulls_enable, xe_modparam.ulls_enable, bool,
> > 0444);
> > +MODULE_PARM_DESC(ulls_enable, "Enable ULLS on migration queue if LR
> > VM open (default: true)");
> > +
> >  module_param_named(vram_bar_size, xe_modparam.force_vram_bar_size,
> > int, 0600);
> >  MODULE_PARM_DESC(vram_bar_size, "Set the vram bar size in MiB
> > (<0=disable-resize, 0=max-needed-size, >0=force-size "
> >                  "[default=" __stringify(XE_DEFAULT_VRAM_BAR_SIZE)
> > "])");
> > diff --git a/drivers/gpu/drm/xe/xe_module.h
> > b/drivers/gpu/drm/xe/xe_module.h
> > index 79cb9639c0f3..f0220b694c40 100644
> > --- a/drivers/gpu/drm/xe/xe_module.h
> > +++ b/drivers/gpu/drm/xe/xe_module.h
> > @@ -12,6 +12,7 @@
> >  struct xe_modparam {
> >         bool force_execlist;
> >         bool probe_display;
> > +       bool ulls_enable;
> >         int force_vram_bar_size;
> >         int guc_log_level;
> >         char *guc_firmware_path;
>