Hi Inki, On 2015-12-11 15:52, Inki Dae wrote: > 2015-12-11 20:27 GMT+09:00 Marek Szyprowski <m.szyprowski at samsung.com>: >> On 2015-12-11 10:57, Inki Dae wrote: >>> 2015ë 12ì 11ì¼ 18:26ì Marek Szyprowski ì´(ê°) ì´ ê¸: >>>> On 2015-12-11 10:02, Inki Dae wrote: >>>>> I found out why NULL point access happened. That was incurred by below >>>>> your patch, >>>>> [PATCH] drm/exynos: move dma_addr attribute from exynos plane to exynos >>>>> fb >>>>> >>>>> When another crtc driver is hotplugged in runtime such as HDMI or VIDI, >>>>> the drm frambuffer object of fb_helper is set to the plane state of the >>>>> new crtc driver >>>>> so the driver should get the drm framebuffer object from the plane's >>>>> state or >>>>> exynos_plane->pending_fb which is set by exynos_plane_atomic_update >>>>> function. >>>>> >>>>> After that, I think the drm framebuffer should be set to drm plane as a >>>>> current fb >>>>> which would be scanned out. >>>>> >>>>> Anyway, I can fix it like below if you are ok. >>>>> >>>>> Thanks, >>>>> Inki Dae >>>>> >>>>> --- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>>> @@ -137,7 +137,7 @@ static void vidi_update_plane(struct exynos_drm_crtc >>>>> *crtc, >>>>> if (ctx->suspended) >>>>> return; >>>>> - addr = exynos_drm_fb_dma_addr(plane->base.fb, 0); >>>>> + addr = exynos_drm_fb_dma_addr(plane->pending_fb, 0); >>>>> DRM_DEBUG_KMS("dma_addr = %pad\n", &addr); >>>>> >>>>> + plane->base.fb = plane->pending_fb; >>>> plane->base.fb should not be modified. I think that the following fix is >>>> more >>> Could you explain why plane->base.fb shouldn't be modified? >> >> All 'base' classes are modified by DRM core and there should be no need >> to modify them from the drivers. > Ok, If so - drm core updates plane->fb - then it's reasonable. But I > couldn't find the exact location where plane->fb is set to a fb to be > scanned out. > So could you let me know the exact location? it's not clear to me yet.
Setting plane->fb is wired somewhere in the atomic update logic, see __setplane_internal() function in drivers/gpu/drm/drm_crtc.c. Some more comments are also in the drm_atomic_clean_old_fb() function in drivers/gpu/drm/drm_atomic.c However I don't know the exact call path. >> I've checked this issue and the proper fix for is the following code: >> >> --- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c >> +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c >> @@ -131,13 +131,14 @@ static void vidi_disable_vblank(struct exynos_drm_crtc >> *crtc) >> static void vidi_update_plane(struct exynos_drm_crtc *crtc, >> struct exynos_drm_plane *plane) >> { >> + struct drm_plane_state *state = plane->base.state; >> struct vidi_context *ctx = crtc->ctx; >> dma_addr_t addr; >> >> if (ctx->suspended) >> return; >> >> - addr = exynos_drm_fb_dma_addr(plane->base.fb, 0); >> + addr = exynos_drm_fb_dma_addr(state->fb, 0); >> DRM_DEBUG_KMS("dma_addr = %pad\n", &addr); >> >> if (ctx->vblank_on) >> >> >> plane->base.fb is updated from the core once all crtc/plane atomic update >> calls finishes. The drivers should use the fb stored in plane->base.state. >> I've missed that VIDI driver doesn't get the fb and incorrectly used >> plane->base.fb instad of state->fb while updating the code. >> > Actually, I used state->fb instead of plane->pending_fb but in > exynos_plane_atomic_update function, plane->pending_fb is set to > state->fb. > That is why I commented like below, > " so the driver should get the drm framebuffer object from the plane's > state or exynos_plane->pending_fb which is set by > exynos_plane_atomic_update function." > > Anyway, using state->fb looks like more consistent with other drivers, > fimd, decon and mixer. Thanks for applying my fix and merging this patch. >>> In case that userspace requests setplane, plane->base.fb would be updated >>> after update_plane callback. >>> However, in other cases, I don't see how plane->base.fb could be updated. >>> In this case, I think vendor specific drivers would need to update it as a >>> current fb to be scanned out like other some drivers did. >>> Of course, it may be possible for drm core part to take care of it >>> appropriately later. >>> >>> Thanks, >>> Inki Dae >>> >>>> appropriate: >>>> --- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>> @@ -132,12 +132,13 @@ static void vidi_update_plane(struct >>>> exynos_drm_crtc *crtc, >>>> struct exynos_drm_plane *plane) >>>> { >>>> struct vidi_context *ctx = crtc->ctx; >>>> - dma_addr_t addr; >>>> + dma_addr_t addr = 0; >>>> >>>> if (ctx->suspended) >>>> return; >>>> >>>> - addr = exynos_drm_fb_dma_addr(plane->base.fb, 0); >>>> + if (plane->base.fb) >>>> + addr = exynos_drm_fb_dma_addr(plane->base.fb, 0); >>>> DRM_DEBUG_KMS("dma_addr = %pad\n", &addr); >>>> >>>> if (ctx->vblank_on) >>>> >>>> I will investigate the case of NULL plane->state.fb, because it might be >>>> relevant >>>> to other crtc drivers as well. >>>> >>>> >>>>> if (ctx->vblank_on) >>>>> >>>>> >>>>> 2015ë 12ì 10ì¼ 22:05ì Inki Dae ì´(ê°) ì´ ê¸: >>>>>> 2015ë 11ì 30ì¼ 22:53ì Marek Szyprowski ì´(ê°) ì´ ê¸: >>>>>>> DMA address is a framebuffer attribute and the right place for it is >>>>>>> exynos_drm_framebuffer not exynos_drm_plane. This patch also >>>>>>> introduces >>>>>>> helper function for getting dma address of the given framebuffer. >>>>>>> >>>>>>> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com> >>>>>>> Reviewed-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk> >>>>>>> --- >>>>>>> drivers/gpu/drm/exynos/exynos5433_drm_decon.c | 13 ++++++++----- >>>>>>> drivers/gpu/drm/exynos/exynos7_drm_decon.c | 16 +++++++++------- >>>>>>> drivers/gpu/drm/exynos/exynos_drm_drv.h | 3 --- >>>>>>> drivers/gpu/drm/exynos/exynos_drm_fb.c | 16 ++++++---------- >>>>>>> drivers/gpu/drm/exynos/exynos_drm_fb.h | 3 +-- >>>>>>> drivers/gpu/drm/exynos/exynos_drm_fimd.c | 10 ++++++---- >>>>>>> drivers/gpu/drm/exynos/exynos_drm_plane.c | 18 >>>>>>> ------------------ >>>>>>> drivers/gpu/drm/exynos/exynos_drm_vidi.c | 5 ++++- >>>>>>> drivers/gpu/drm/exynos/exynos_mixer.c | 7 ++++--- >>>>>>> 9 files changed, 38 insertions(+), 53 deletions(-) >>>>>>> >>>>>> <--snip--> >>>>>> >>>>>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>>>>> b/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>>>>> index 669362c53f49..3ce141236fad 100644 >>>>>>> --- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>>>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c >>>>>>> @@ -24,6 +24,7 @@ >>>>>>> #include "exynos_drm_drv.h" >>>>>>> #include "exynos_drm_crtc.h" >>>>>>> +#include "exynos_drm_fb.h" >>>>>>> #include "exynos_drm_plane.h" >>>>>>> #include "exynos_drm_vidi.h" >>>>>>> @@ -126,11 +127,13 @@ static void vidi_update_plane(struct >>>>>>> exynos_drm_crtc *crtc, >>>>>>> struct exynos_drm_plane *plane) >>>>>>> { >>>>>>> struct vidi_context *ctx = crtc->ctx; >>>>>>> + dma_addr_t addr; >>>>>>> if (ctx->suspended) >>>>>>> return; >>>>>>> - DRM_DEBUG_KMS("dma_addr = %pad\n", plane->dma_addr); >>>>>>> + addr = exynos_drm_fb_dma_addr(plane->base.fb, 0); >>>>>> At this point, plane->base.fb is NULL so null pointer access happens >>>>>> like below, >>>>>> >>>>>> [ 5.969422] Unable to handle kernel NULL pointer dereference at >>>>>> virtual address 00000090 >>>>>> [ 5.977481] pgd = ee590000 >>>>>> [ 5.980142] [00000090] *pgd=6e526831, *pte=00000000, *ppte=00000000 >>>>>> [ 5.986347] Internal error: Oops: 17 [#1] PREEMPT SMP ARM >>>>>> [ 5.991712] Modules linked in: >>>>>> [ 5.994770] CPU: 3 PID: 1598 Comm: sh Not tainted >>>>>> 4.4.0-rc3-00052-gc60d7e2-dirty #199 >>>>>> [ 6.002565] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) >>>>>> [ 6.008647] task: ef328000 ti: ee4d4000 task.ti: ee4d4000 >>>>>> [ 6.014053] PC is at exynos_drm_fb_dma_addr+0x8/0x14 >>>>>> [ 6.018990] LR is at vidi_update_plane+0x4c/0xc4 >>>>>> [ 6.023581] pc : [<c02b1fb4>] lr : [<c02c3cc4>] psr: 80000013 >>>>>> [ 6.023581] sp : ee4d5d90 ip : 00000001 fp : 00000000 >>>>>> [ 6.035029] r10: 00000000 r9 : c05b965c r8 : ee813e00 >>>>>> [ 6.040241] r7 : 00000000 r6 : ee8e3330 r5 : 00000000 r4 : >>>>>> ee8e3010 >>>>>> [ 6.046749] r3 : 00000000 r2 : 00000000 r1 : 00000024 r0 : >>>>>> 00000000 >>>>>> [ 6.053264] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM >>>>>> Segment none >>>>>> [ 6.060379] Control: 10c5387d Table: 6e59004a DAC: 00000051 >>>>>> [ 6.066107] Process sh (pid: 1598, stack limit = 0xee4d4210) >>>>>> [ 6.071748] Stack: (0xee4d5d90 to 0xee4d6000) >>>>>> [ 6.076100] 5d80: 00000000 >>>>>> ee813300 ee476e40 00000005 >>>>>> [ 6.084236] 5da0: ee8e3330 c028ac14 00000008 ee476e40 ee476fc0 >>>>>> ef3b3800 ee476fc0 eeb3e380 >>>>>> [ 6.092395] 5dc0: 00000002 c02b08e4 00000000 eeb3e3a4 ee476fc0 >>>>>> ee476e40 ef3b3800 eeb3e380 >>>>>> [ 6.100554] 5de0: 00000002 c02b12b8 ee854400 00000000 00000001 >>>>>> ee8501a8 00000000 ee476e40 >>>>>> [ 6.108714] 5e00: ef3b3800 00000001 ee476e40 00000050 ee850c80 >>>>>> 00000001 ee476e40 ef3b3aac >>>>>> [ 6.116873] 5e20: 00000002 000000ff 00000000 c028e0ec 000a82b4 >>>>>> c02acc50 ee8e36a0 ee476c80 >>>>>> [ 6.125032] 5e40: ef3b3aac ef3b3800 ee476c9c ee850c80 ef3b3800 >>>>>> ef3b3800 ef3b3800 ef3b398c >>>>>> [ 6.133191] 5e60: c088c390 00000002 000a82b4 c028f8d4 00000000 >>>>>> ef3b3800 ef0f4300 c028f948 >>>>>> [ 6.141350] 5e80: ee850c80 c028f864 ef3b3a84 00000001 ef3b3a90 >>>>>> c02853e4 00000001 00000000 >>>>>> [ 6.149509] 5ea0: 000a82b4 ee4d5ec0 00000002 ee8e3010 00000002 >>>>>> 00000002 ee4d5f88 00000000 >>>>>> [ 6.157669] 5ec0: 00000000 eeb8df00 000a82b4 c02c4278 00000002 >>>>>> ee476b00 eeb8df0c c01390ac >>>>>> [ 6.165828] 5ee0: 00000000 00000000 ee4e1f00 00000002 000a9540 >>>>>> ee4d5f88 c000f844 ee4d4000 >>>>>> [ 6.173987] 5f00: 00000000 c00dbf70 000a82b4 c00093dc ee4d4000 >>>>>> ee4d5f78 ef328234 c0579bec >>>>>> [ 6.182146] 5f20: 00000001 00000001 ee4d5f3c 00000001 ee45e9c4 >>>>>> 00000001 000a82b4 c005ca74 >>>>>> [ 6.190306] 5f40: ee45e9c4 00000002 000a9540 c005cad4 ee4e1f00 >>>>>> 00000002 000a9540 ee4d5f88 >>>>>> [ 6.198465] 5f60: c000f844 c00dc770 00000000 00000000 ee4e1f00 >>>>>> ee4e1f00 00000002 000a9540 >>>>>> [ 6.206624] 5f80: c000f844 c00dcf98 00000000 00000000 00000003 >>>>>> 000a7c40 00000001 000a9540 >>>>>> [ 6.214783] 5fa0: 00000004 c000f680 000a7c40 00000001 00000001 >>>>>> 000a9540 00000002 00000000 >>>>>> [ 6.222942] 5fc0: 000a7c40 00000001 000a9540 00000004 00000020 >>>>>> 000a82c8 000a8294 000a82b4 >>>>>> [ 6.231102] 5fe0: 00000000 be8b1624 00012345 b6e94166 40000030 >>>>>> 00000001 00000000 00000000 >>>>>> [ 6.239270] [<c02b1fb4>] (exynos_drm_fb_dma_addr) from [<c02c3cc4>] >>>>>> (vidi_update_plane+0x4c/0xc4) >>>>>> [ 6.248122] [<c02c3cc4>] (vidi_update_plane) from [<c028ac14>] >>>>>> (drm_atomic_helper_commit_planes+0x1f4/0x258) >>>>>> [ 6.257928] [<c028ac14>] (drm_atomic_helper_commit_planes) from >>>>>> [<c02b08e4>] (exynos_atomic_commit_complete+0xe4/0x1c4) >>>>>> [ 6.268688] [<c02b08e4>] (exynos_atomic_commit_complete) from >>>>>> [<c02b12b8>] (exynos_atomic_commit+0x180/0x1cc) >>>>>> [ 6.278584] [<c02b12b8>] (exynos_atomic_commit) from [<c028e0ec>] >>>>>> (restore_fbdev_mode+0x260/0x290) >>>>>> [ 6.287525] [<c028e0ec>] (restore_fbdev_mode) from [<c028f8d4>] >>>>>> (drm_fb_helper_restore_fbdev_mode_unlocked+0x30/0x74) >>>>>> [ 6.298111] [<c028f8d4>] (drm_fb_helper_restore_fbdev_mode_unlocked) >>>>>> from [<c028f948>] (drm_fb_helper_set_par+0x30/0x54) >>>>>> [ 6.308961] [<c028f948>] (drm_fb_helper_set_par) from [<c028f864>] >>>>>> (drm_fb_helper_hotplug_event+0x9c/0xdc) >>>>>> [ 6.318595] [<c028f864>] (drm_fb_helper_hotplug_event) from >>>>>> [<c02853e4>] (drm_helper_hpd_irq_event+0xd4/0x160) >>>>>> [ 6.328578] [<c02853e4>] (drm_helper_hpd_irq_event) from >>>>>> [<c02c4278>] (vidi_store_connection+0x94/0xcc) >>>>>> [ 6.337954] [<c02c4278>] (vidi_store_connection) from [<c01390ac>] >>>>>> (kernfs_fop_write+0xb8/0x1bc) >>>>>> [ 6.346723] [<c01390ac>] (kernfs_fop_write) from [<c00dbf70>] >>>>>> (__vfs_write+0x20/0xd8) >>>>>> [ 6.354531] [<c00dbf70>] (__vfs_write) from [<c00dc770>] >>>>>> (vfs_write+0x90/0x164) >>>>>> [ 6.361821] [<c00dc770>] (vfs_write) from [<c00dcf98>] >>>>>> (SyS_write+0x44/0x9c) >>>>>> [ 6.368855] [<c00dcf98>] (SyS_write) from [<c000f680>] >>>>>> (ret_fast_syscall+0x0/0x3c) >>>>>> [ 6.376404] Code: eb0b17f1 eaffffe7 e3510003 d2811024 (d7900101) >>>>>> >>>>>> When vidi driver is intiated by triggering a connection sysfs file, >>>>>> vidi driver tries modeset binding by calling drm_fb_helper_hotplug_event. >>>>>> However, at this time it seems there is a case that plan->state->crtc >>>>>> exists but plane->fb is NULL, which would be related to vidi driver. >>>>>> >>>>>> I just looked into this issue roughly so we would need to check this >>>>>> issue in more details. >>>>>> >>>>>> Thanks, >>>>>> Inki Dae >>>>>> >>>>>>> + DRM_DEBUG_KMS("dma_addr = %pad\n", &addr); >>>>>>> if (ctx->vblank_on) >>>>>>> schedule_work(&ctx->work); >>>>>>> diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c >>>>>>> b/drivers/gpu/drm/exynos/exynos_mixer.c >>>>>>> index 47777be1a754..f40de82848dc 100644 >>>>>>> --- a/drivers/gpu/drm/exynos/exynos_mixer.c >>>>>>> +++ b/drivers/gpu/drm/exynos/exynos_mixer.c >>>>>>> @@ -37,6 +37,7 @@ >>>>>>> #include "exynos_drm_drv.h" >>>>>>> #include "exynos_drm_crtc.h" >>>>>>> +#include "exynos_drm_fb.h" >>>>>>> #include "exynos_drm_plane.h" >>>>>>> #include "exynos_drm_iommu.h" >>>>>>> @@ -422,8 +423,8 @@ static void vp_video_buffer(struct >>>>>>> mixer_context *ctx, >>>>>>> return; >>>>>>> } >>>>>>> - luma_addr[0] = plane->dma_addr[0]; >>>>>>> - chroma_addr[0] = plane->dma_addr[1]; >>>>>>> + luma_addr[0] = exynos_drm_fb_dma_addr(fb, 0); >>>>>>> + chroma_addr[0] = exynos_drm_fb_dma_addr(fb, 1); >>>>>>> if (mode->flags & DRM_MODE_FLAG_INTERLACE) { >>>>>>> ctx->interlace = true; >>>>>>> @@ -575,7 +576,7 @@ static void mixer_graph_buffer(struct >>>>>>> mixer_context *ctx, >>>>>>> dst_y_offset = plane->crtc_y; >>>>>>> /* converting dma address base and source offset */ >>>>>>> - dma_addr = plane->dma_addr[0] >>>>>>> + dma_addr = exynos_drm_fb_dma_addr(fb, 0) >>>>>>> + (plane->src_x * fb->bits_per_pixel >> 3) >>>>>>> + (plane->src_y * fb->pitches[0]); >>>>>>> src_x_offset = 0; >>>>>>> >>>>>>> >>>>>>> Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland