From 91aa8d91b54a2f9393d9582925464948b673601d Mon Sep 17 00:00:00 2001 From: Arthur Hanson Rasmusson Date: Thu, 12 Nov 2026 01:32:25 -0500 Subject: vgsp: aperture-aware foreign USERD guard and wire fallback c24 (V30) skipped the X/GLX channel's own sysmem USERD block because the same numeric PA 0x8f0000 is owned by the RC watchdog channel in vidmem; the X server then failed with 'Failed to initialize DMA' and 'Failed to allocate push buffer'. Compare the aperture as well as the page, and keep base 0 + userdOffset as a fallback when the client memory-object table cannot name the USERD (the resolver still wins when it has a verified object). This restores the c23 X bring-up while keeping the fail-closed table path. Validation pending a fresh V31 cycle: X starts, glxinfo/glxgears, chan_dump userd page/aper, and the USERD resolution/fallback witness lines. --- kernel/gsp_rm_emulation.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel/gsp_rm_emulation.c') diff --git a/kernel/gsp_rm_emulation.c b/kernel/gsp_rm_emulation.c index 9ba17c8..4420810 100644 --- a/kernel/gsp_rm_emulation.c +++ b/kernel/gsp_rm_emulation.c @@ -3793,6 +3793,8 @@ static void gsp_rm_register_channel(struct gsp_emu_context *ctx, u32 h_client, * USERD zero (the service must never write a guessed block). */ if (userd_wire_base == 0) { + u64 wire_pa = desc.userd_pa; + u32 wire_as = desc.userd_as; u32 h_userd = 0; desc.userd_pa = 0; @@ -3813,6 +3815,24 @@ static void gsp_rm_register_channel(struct gsp_emu_context *ctx, u32 h_client, h_userd, uo); } + /* + * CONT.438b: the X/GLX kernel channel needs its + * wire-derived block until the client memory-object + * table can name the real USERD. c24 (V30) cleared + * it and X failed "Failed to initialize DMA"/ + * "Failed to allocate push buffer"; c23 (V28) used + * base 0 + userdOffset and X started. Keep the old + * value as a fallback, but only when it is a real + * 4K-backed offset (the resolver still wins when it + * has a verified memory object). + */ + if (!desc.userd_pa && wire_pa) { + desc.userd_pa = wire_pa; + desc.userd_as = wire_as; + pr_info_ratelimited("vgsp-rm: chan USERD hObject=0x%x hUserd=0x%x unresolved; fallback to wire base+offset=0x%llx as=%u (no guessed table PA)\n", + h_object, h_userd, + wire_pa, wire_as); + } } } memcpy(&desc.notifier_pa, params + GSPRM_CHAN_NOTIFIER_MEM, 8); -- cgit v1.2.3