On Wed, Jun 19, 2024 at 04:11:08PM +0300, Jani Nikula wrote: > On Wed, 19 Jun 2024, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > On Tue, Jun 18, 2024 at 02:07:56PM +0300, Jani Nikula wrote: > >> On Tue, 11 Jun 2024, Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > >> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > >> > > >> > As we extend the use of DSB for critical pipe/plane register > >> > programming, it'll be nice to have an escape valve at hand, > >> > in case things go very poorly. To that end, add a i915.enable_dsb > >> > modparam by which we can force the driver to take the pure mmio > >> > path instead. > >> > > >> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > >> > --- > >> > drivers/gpu/drm/i915/display/intel_display_params.c | 3 +++ > >> > drivers/gpu/drm/i915/display/intel_display_params.h | 1 + > >> > drivers/gpu/drm/i915/display/intel_dsb.c | 3 +++ > >> > 3 files changed, 7 insertions(+) > >> > > >> > diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c > >> > index aebdb7b59dbf..449a31767791 100644 > >> > --- a/drivers/gpu/drm/i915/display/intel_display_params.c > >> > +++ b/drivers/gpu/drm/i915/display/intel_display_params.c > >> > @@ -54,6 +54,9 @@ intel_display_param_named_unsafe(enable_dc, int, 0400, > >> > intel_display_param_named_unsafe(enable_dpt, bool, 0400, > >> > "Enable display page table (DPT) (default: true)"); > >> > > >> > +intel_display_param_named_unsafe(enable_dsb, bool, 0600, > >> > + "Enable display state buffer (DSB) (default: true)"); > >> > >> Not much point in leaving the module param 0600, is there? > > > > It'll let you try both dsb and mmio paths at runtime without > > having to do a full reboot/reload. > > I mean does any code actually look at the *module* parameter runtime? > It's only the initial value for the device param? You can change it via the debugfs i915_params/* thing. -- Ville Syrjälä Intel
