On Mon, 18 Jan 2021, Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> wrote: > On 2021.01.15 13:01:49 +0200, Joonas Lahtinen wrote: >> Quoting Jani Nikula (2021-01-15 12:50:54) >> > On Thu, 14 Jan 2021, Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> wrote: >> > > On 2021.01.14 08:58:19 +0800, Xiong Zhang wrote: >> > >> From: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> >> > >> >> > >> Some vmm like hyperv and crosvm don't supply any ISA bridge to their guest, >> > >> when igd passthrough is equipped on these vmm, guest i915 display may >> > >> couldn't work as guest i915 detects PCH_NONE pch type. >> > >> >> > >> When i915 runs as guest, this patch guess pch type through gpu type even >> > >> without ISA bridge. >> > >> >> > >> v2: Fix CI warning >> > >> v3: Add HAS_DISPLAY()= true condition beforce guessing virt pch, then >> > >> refactori. >> > >> v4: Fix CI warning >> > >> >> > >> Signed-off-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> >> > >> Signed-off-by: Xiong Zhang <xiong.y.zhang@xxxxxxxxx> >> > >> --- >> > >> drivers/gpu/drm/i915/i915_drv.h | 7 +++++- >> > >> drivers/gpu/drm/i915/intel_pch.c | 39 ++++++++++++++++++-------------- >> > >> 2 files changed, 28 insertions(+), 18 deletions(-) >> > >> >> > > >> > > Good to me, thanks! I think this should change author to you. :) >> > > >> > > Reviewed-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> >> > >> > Pushed to drm-intel-next, thanks for the patch and review. I ended up >> > retaining Zhenyu's authorship, and added >> > >> > Co-developed-by: Xiong Zhang <xiong.y.zhang@xxxxxxxxx> >> >> This only works for the majority of SKUs which happen to use the PCH >> that is most common. I NAKed very similar patch some years back asking >> for a reliable means to detect the PCH type instead. >> >> Has there been any attempt to introduce such mechanism? >> > > I think the situation is that if just passing through GPU device, as > full device model depends on userspace VMM, we have no way to properly > detect PCH type from device, e.g in case of one GEN device which could > live with two or more different PCH types. It's better if either we > have properly defined way to detect through GPU device or display arch > always defines CPU/PCH display in pair. > > Currently this tries to assume PCH with best effort that fixed bunch of > problems. On really mismatch case, how about adding i915 parameter to > override PCH type? As that won't add dependency on other components.. In general, module parameters should not be considered a fix or a solution. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
