> -----Original Message-----
> From: De Marchi, Lucas <lucas.demarchi@xxxxxxxxx>
> Sent: Tuesday, September 10, 2024 9:13 PM
> To: Vivi, Rodrigo <rodrigo.vivi@xxxxxxxxx>
> Cc: Bommu, Krishnaiah <krishnaiah.bommu@xxxxxxxxx>; intel-
> xe@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Kamil Konieczny
> <kamil.konieczny@xxxxxxxxxxxxxxx>; Ceraolo Spurio, Daniele
> <daniele.ceraolospurio@xxxxxxxxx>; Upadhyay, Tejas
> <tejas.upadhyay@xxxxxxxxx>; Tvrtko Ursulin <tursulin@xxxxxxxxxxx>; Joonas
> Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>; Nikula, Jani
> <jani.nikula@xxxxxxxxx>; Thomas Hellström
> <thomas.hellstrom@xxxxxxxxxxxxxxx>; Teres Alexis, Alan Previn
> <alan.previn.teres.alexis@xxxxxxxxx>; Winkler, Tomas
> <tomas.winkler@xxxxxxxxx>; Usyskin, Alexander
> <alexander.usyskin@xxxxxxxxx>
> Subject: Re: [PATCH v2] drm: Ensure Proper Unload/Reload Order of MEI
> Modules for i915/Xe Driver
>
> On Tue, Sep 10, 2024 at 11:03:30AM GMT, Rodrigo Vivi wrote:
> >On Mon, Sep 09, 2024 at 09:33:17AM +0530, Bommu Krishnaiah wrote:
> >> This update addresses the unload/reload sequence of MEI modules in
> >> relation to the i915/Xe graphics driver. On platforms where the MEI
> >> hardware is integrated with the graphics device (e.g., DG2/BMG), the
> >> i915/xe driver is depend on the MEI modules. Conversely, on newer
> >> platforms like MTL and LNL, where the MEI hardware is separate, this
> dependency does not exist.
> >>
> >> The changes introduced ensure that MEI modules are unloaded and
> >> reloaded in the correct order based on platform-specific
> >> dependencies. This is achieved by adding a MODULE_SOFTDEP directive to
> the i915 and Xe module code.
>
>
> can you explain what causes the modules to be loaded today? Also, is this to fix
> anything related to *loading* order or just unload?
>
> >>
> >> These changes enhance the robustness of MEI module handling across
> >> different hardware platforms, ensuring that the i915/Xe driver can be
> >> cleanly unloaded and reloaded without issues.
> >>
> >> v2: updated commit message
> >>
> >> Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu@xxxxxxxxx>
> >> Cc: Kamil Konieczny <kamil.konieczny@xxxxxxxxxxxxxxx>
> >> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
> >> Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> >> Cc: Tejas Upadhyay <tejas.upadhyay@xxxxxxxxx>
> >> ---
> >> drivers/gpu/drm/i915/i915_module.c | 2 ++
> >> drivers/gpu/drm/xe/xe_module.c | 2 ++
> >> 2 files changed, 4 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/i915/i915_module.c
> >> b/drivers/gpu/drm/i915/i915_module.c
> >> index 65acd7bf75d0..2ad079ad35db 100644
> >> --- a/drivers/gpu/drm/i915/i915_module.c
> >> +++ b/drivers/gpu/drm/i915/i915_module.c
> >> @@ -75,6 +75,8 @@ static const struct { }; static int
> >> init_progress;
> >>
> >> +MODULE_SOFTDEP("pre: mei_gsc_proxy mei_gsc");
> >> +
> >> static int __init i915_init(void)
> >> {
> >> int err, i;
> >> diff --git a/drivers/gpu/drm/xe/xe_module.c
> >> b/drivers/gpu/drm/xe/xe_module.c index bfc3deebdaa2..5633ea1841b7
> >> 100644
> >> --- a/drivers/gpu/drm/xe/xe_module.c
> >> +++ b/drivers/gpu/drm/xe/xe_module.c
> >> @@ -127,6 +127,8 @@ static void xe_call_exit_func(unsigned int i)
> >> init_funcs[i].exit();
> >> }
> >>
> >> +MODULE_SOFTDEP("pre: mei_gsc_proxy mei_gsc");
> >
> >I'm honestly not very comfortable with this.
> >
> >1. This is not true for every device supported by these modules.
> >2. This is not true for every (and the most basic) functionality of these drivers.
> >
> >Shouldn't this be done in the the mei side?
>
> I don't think it's possible to do from the mei side. Would mei depend on both xe
> and i915 (and thus cause both to be loaded regardless of the platform?). For a
> runtime dependency like this that depends on the platform, I think the best way
> would be a weakdep + either a request_module() or something else that causes
> the module to load (is that what comp_* is doing today?)
>
> >
> >Couldn't at probe we identify the need of them and if needed we return
> >-EPROBE to attempt a retry after the mei drivers were probed?
>
> I'm not sure this is fixing anything for probe. I think we already wait on the other
> component to be ready without blocking the rest of the driver functionality.
>
> A weakdep wouldn't cause the module to be loaded where it's not needed, but
> need some clarification if this is trying to fix anything load-related or just unload.
This change is fixing unload.
During xe load I am seeing mei_gsc modules was loaded, but not unloaded during the unload xe
root@DUT6127BMGFRD:/home/gta# lsmod | grep xe ------>>>just after system reboot
root@DUT6127BMGFRD:/home/gta#
root@DUT6127BMGFRD:/home/gta# lsmod | grep mei
mei_hdcp 28672 0
mei_pxp 16384 0
mei_me 49152 2
mei 167936 5 mei_hdcp,mei_pxp,mei_me
root@DUT6127BMGFRD:/home/gta# lsmod | grep xe
root@DUT6127BMGFRD:/home/gta#
root@DUT6127BMGFRD:/home/gta# modprobe xe
root@DUT6127BMGFRD:/home/gta#
root@DUT6127BMGFRD:/home/gta# lsmod | grep mei
mei_gsc_proxy 16384 0
mei_gsc 12288 1
mei_hdcp 28672 0
mei_pxp 16384 0
mei_me 49152 3 mei_gsc
mei 167936 8 mei_gsc_proxy,mei_gsc,mei_hdcp,mei_pxp,mei_me
root@DUT6127BMGFRD:/home/gta#
root@DUT6127BMGFRD:/home/gta#
root@DUT6127BMGFRD:/home/gta#
root@DUT6127BMGFRD:/home/gta# init 3
root@DUT6127BMGFRD:/home/gta# echo -n auto > /sys/bus/pci/devices/0000\:03\:00.0/power/control
root@DUT6127BMGFRD:/home/gta# echo -n "0000:03:00.0" > /sys/bus/pci/drivers/xe/unbind
root@DUT6127BMGFRD:/home/gta# modprobe -r xe
root@DUT6127BMGFRD:/home/gta#
root@DUT6127BMGFRD:/home/gta# lsmod | grep xe
root@DUT6127BMGFRD:/home/gta# lsmod | grep mei
mei_gsc_proxy 16384 0
mei_gsc 12288 0
mei_hdcp 28672 0
mei_pxp 16384 0
mei_me 49152 3 mei_gsc
mei 167936 7 mei_gsc_proxy,mei_gsc,mei_hdcp,mei_pxp,mei_me
root@DUT6127BMGFRD:/home/gta#
Regards,
Krishna.
>
> Lucas De Marchi
>
> >
> >Cc: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
> >Cc: Tomas Winkler <tomas.winkler@xxxxxxxxx>
> >Cc: Alan Previn <alan.previn.teres.alexis@xxxxxxxxx>
> >Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
> >Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> >Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> >Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> >Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> >Cc: Tvrtko Ursulin <tursulin@xxxxxxxxxxx>
> >
> >> +
> >> static int __init xe_init(void)
> >> {
> >> int err, i;
> >> --
> >> 2.25.1
> >>
