On 15 March 2016 at 02:30, Mark yao wrote: > On 2016年03月14日 21:35, Tomeu Vizoso wrote: >> >> On 2 December 2014 at 10:15, Mark Yao wrote: >>> >>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c >>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c >>> new file mode 100644 >>> index 0000000..e7ca25b >>> --- /dev/null >>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c >>> @@ -0,0 +1,1455 @@ >> >> ... >>> >>> +static bool vop_crtc_mode_fixup(struct drm_crtc *crtc, >>> + const struct drm_display_mode *mode, >>> + struct drm_display_mode *adjusted_mode) >>> +{ >>> + if (adjusted_mode->htotal == 0 || adjusted_mode->vtotal == 0) >>> + return false; >> >> Hi Mark, >> >> what's the rationale for this? >> >> Disabling a CRTC as in [0] will cause mode_fixup() to be called with >> an empty mode, failing that test. >> >> Removing the check seems to get things working fine for a short while, >> but a later modeset invariably gets the VOP to hang (as reported by >> [1]). >> >> Do you know why that check was put in place and what exactly could be >> causing the hw to hang? >> >> [0] >> https://cgit.freedesktop.org/xorg/app/intel-gpu-tools/tree/lib/igt_kms.c#n1616 >> [1] >> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/gpu/drm/rockchip/rockchip_drm_vop.c#n873 >> >> Thanks, >> >> Tomeu >> > Hi Tomeu > > Just thinking that "adjusted_mode->htotal == 0 || adjusted_mode->vtotal == > 0" is not a good mode for vop. Ah, ok. Guess it should be removed then so we don't break userspace? > And you said VOP hang, only WARN_ON error message? or system hang, die? Sorry, the symptom was only the warning, I just went a bit too far and assumed the VOP had stopped working at all. > I think maybe crtc disable too fast, vblank is off, then no one can feed the > wait_update_complete. > Can you test it again with following patch? Actually, in today's testing I don't see that happening any more, sorry about that :/ What I have been looking at today is a related issue when running the kms_flip_event_leak test from intel-gpu-tools. If I remove the check mentioned above so CRTCs can be disabled with the SetCRTC IOCTL, I see this page fault the second and subsequent times I run the test. [ 75.809031] rk_iommu ff930300.iommu: Page fault at 0x01000000 of type read [ 75.809035] rk_iommu ff930300.iommu: iova = 0x01000000: dte_index: 0x4 pte_index: 0x0 page_offset: 0x0 [ 75.809040] rk_iommu ff930300.iommu: mmu_dte_addr: 0x2c258000 dte@0x2c258010: 0x2c561001 valid: 1 pte@0x2c561000: 0x2a000006 valid: 0 page@0x00000000 flags: 0x0 [ 76.951288] rk_iommu ff930300.iommu: Enable stall request timed out, status: 0x00004b I have written a smaller standalone test that is attached in case you want to check it out, but I haven't been able to find out why it only happens when the test is rerun. Apparently the VOP is still trying to read a BO (0x01000000) right when the kernel frees it, but from what I can see, it should be scanning another BO at that point. Do you have any ideas on what could be happening? Thanks, Tomeu > drivers/gpu/drm/rockchip/rockchip_drm_vop.c > @@ -503,6 +503,8 @@ static void vop_crtc_disable(struct drm_crtc *crtc) > if (!vop->is_enabled) > return; > + vop_crtc_wait_for_update(crtc); > + > drm_crtc_vblank_off(crtc); > > Thanks. > > -- > Ｍark Yao > >