On Tue, Mar 3, 2026 at 2:32 PM Dmitry Baryshkov <[email protected]> wrote: > > On Tue, Mar 03, 2026 at 10:35:46AM -0800, Rob Clark wrote: > > On Sun, Feb 22, 2026 at 12:32 PM Dmitry Baryshkov > > <[email protected]> wrote: > > > > > > On Mon, Feb 23, 2026 at 12:40:10AM +0530, Mahadevan P wrote: > > > > On targets 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. > > > > > > > > Enable separate_gpu_kms by default to decouple GPU and display subsystem > > > > probing. This allows each display subsystem to initialize independently, > > > > ensuring that all display subsystems are probed. > > > > > > > > Signed-off-by: Mahadevan P <[email protected]> > > > > --- > > > > Depends on: > > > > > > > > https://lore.kernel.org/lkml/[email protected]/ > > > > > > > > https://lore.kernel.org/all/[email protected]/ > > > > > > What exactly depends on this patchset? > > > > > > > --- > > > > drivers/gpu/drm/msm/msm_drv.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/gpu/drm/msm/msm_drv.c > > > > b/drivers/gpu/drm/msm/msm_drv.c > > > > index ed2a61c66ac9..65119fb3dfa2 100644 > > > > --- a/drivers/gpu/drm/msm/msm_drv.c > > > > +++ b/drivers/gpu/drm/msm/msm_drv.c > > > > @@ -54,7 +54,7 @@ static bool modeset = true; > > > > MODULE_PARM_DESC(modeset, "Use kernel modesetting [KMS] (1=on > > > > (default), 0=disable)"); > > > > module_param(modeset, bool, 0600); > > > > > > > > -static bool separate_gpu_kms; > > > > +static bool separate_gpu_kms = true; > > > > MODULE_PARM_DESC(separate_gpu_drm, "Use separate DRM device for the > > > > GPU (0=single DRM device for both GPU and display (default), 1=two DRM > > > > devices)"); > > > > module_param(separate_gpu_kms, bool, 0400); > > > > > > The patch LGTM, but I'd prefer to get confirmation from Rob. > > > > I prefer to be a bit more paranoid.. perhaps switch this to a tri-state: > > > > -1: separate drm devices if there is more than one dpu or gpu, > > otherwise, single combined drm device [default] > > 0: single drm device (matching up pairs of dpu and gpu if needed) > > 1: separate drm devices > > > > This way we aren't changing (or breaking) things for existing users. > > I'd rather break things and hear about them being broken.
You are assuming you'd hear about the non-obvious breakages immediately.. I don't think that is a good assumption. To be clear, I'll NAK any change to the default for "normal" hw configurations. If you want to change the modparam to tri-state so that "weird" hw configurations get split devices, I guess I'd be ok with that. At least it limits the potential fallout. BR, -R > > > > BR, > > -R > > > > > BTW: have you tested it with X11? Are you still getting accelerated GPU? > > > > > > -- > > > With best wishes > > > Dmitry > > -- > With best wishes > Dmitry
