From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794062697; b=dwMNjkxVseNwZGnlqgr5BgQgLF7jUuYlyadn7EwldJcQnWujU4dzy1dnknoIz30n1My3 jl/UhbwikvRm5+Xc0EfgOXN+qTXPlXadv/9L8xReVReElr96MNKpWRBPj6z+xqu0PdfwK VfGRBJxzP+fMBC234Gw5jTXojkakrAvFwnuejdCkUYKThNvrazq/m1dJd00kGT3I/NHCp gCHJT0U0q5AAVHoganjS1U7lnN18TBwA2yIEsXlMzblhtyp1LD89sz4c+ailoqZWm50eP 41ff4Ghr7h2sXrH8J7T/m4G15P116SeXP7/lBnGSrymMDJmhH8SR4QFxQs0O3B1k6vw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794062697; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=Av9iBpjbrifvIVaQ4/ZkPW37kUGJ1pP8wCcriTkTOFU=; b=sYuAr30NFLXKqNaVgXHjFhxEfZ6WydiUtgFPXiexi69wUHNQ+2BvCbENaeTrbkMtlZH9 pYBTsK2UcETEwwJBWGt4yTHQRGhymUFaO1EuxnFsRdUYVZvlok/jxPKddf2mjZJdTouzj q8pD/5Dw7F8XrOjnjW6BbJJRtVfH/JdT4PlMwL1CqpKuH8OcmWB6SciJsoXO5GDd2mUVM hwoAy/sfiRavp5UPiJJ04HvEtIfFBn/rMznR0yPw5TFApJtpGwT6BXtU1ddh2lNqDh5Pn 4gVTGnI0SCjSdU1hkAu68mArK7lgidnUk+pciiY+4Gv/JJ1tzVlXVTkYTYmhsfyoJgw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=qND0HwdD; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 383A2606A326; Sat, 7 Nov 2026 14:44:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=qND0HwdD Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA76D1F0089F; Sat, 7 Nov 2026 14:44:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794062697; bh=Av9iBpjbrifvIVaQ4/ZkPW37kUGJ1pP8wCcriTkTOFU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qND0HwdDhQ99BMXKuTiOzu910JAixwW2+SuY3dbXJ7P4IUq0wtHCUf/R9Iq6D3arZ 1mz8QX3w+rnJzoiCQ9nABwZXcR4UI9aLX5Zj4nkza79Dm8egXUeKgpsYdgLGE30H+n XWXTJ4npbz1T76aBm5/zWs95fp8Q/pl7zLybhIio= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fab Stz , Marek Czernohous , Lyude Paul , Sasha Levin Subject: [PATCH 6.18 023/869] drm/nouveau/pci: use config-space MSI rearm on MCP79/MCP7A (NVAC) Date: Sat, 7 Nov 2026 08:45:05 -0500 Message-ID: <20261107134852.846660307@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Czernohous [ Upstream commit 354d47fb3f35461b7f942831c1b2a7105e92b57f ] NVAC (MCP79/MCP7A) uses g94_pci_func, whose .msi_rearm is nv40_pci_msi_rearm(): a re-arm write through the MMIO mirror of PCI config space. On this IGP that path is unreliable; when a re-arm is missed the interrupt line stays dead, command submission times out and the GPU appears hung until reboot. On an Apple Mac mini (early 2009, MCP79, boot0 0x0ac080b1) this showed as sporadic fifo timeouts and GPU hangs under load unless MSI was disabled via config=NvMSI=0. Give NVAC its own pci func that re-arms through real PCI config space (nv46_pci_msi_rearm) instead. This follows existing precedent: nv46.c documents the MMIO-mirror re-arm as broken on several related parts, and commit 5112abc6a433 ("drm/nouveau/pci/g92: Fix rearm") fixed g92 the same way while moving the remaining chipsets, NVAC included, into the newly added shared g94 table, where NVAC stayed on the MMIO path. This change completes that fix for NVAC. The sibling IGP NVAA (MCP77/MCP78) has MSI disabled entirely as "reported broken" in nvkm_pci_new_(); NVAC works correctly once the re-arm goes through config space, so disabling MSI is not necessary. Only NVAC is switched: that is the hardware this has been validated on. The other users of g94_pci_func (G94/G96/G98/GT2xx and the MCP77/MCP89 IGPs) keep their current behavior; MCP77 and MCP89 plausibly want the same treatment but were not tested. Tested on the Mac mini as a daily driver for two months with MSI enabled and zero fifo timeouts. Independently confirmed stable on an iMac9,1 (MCP79) running 6.12.90 with the v1 form of this change (the same one-line functional switch, applied to that kernel's g94 implementation). Fixes: 5112abc6a433 ("drm/nouveau/pci/g92: Fix rearm") Cc: # v6.16+ Tested-by: Fab Stz Assisted-by: Claude:claude-opus-4-7 Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Marek Czernohous Reviewed-by: Lyude Paul Signed-off-by: Lyude Paul Link: https://patch.msgid.link/178688574401.522643.12812428444459119913@gmail.com Signed-off-by: Sasha Levin --- .../gpu/drm/nouveau/include/nvkm/subdev/pci.h | 1 + .../gpu/drm/nouveau/nvkm/engine/device/base.c | 2 +- .../gpu/drm/nouveau/nvkm/subdev/pci/Kbuild | 1 + .../gpu/drm/nouveau/nvkm/subdev/pci/mcp79.c | 35 +++++++++++++++++++ 4 files changed, 38 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/nouveau/nvkm/subdev/pci/mcp79.c diff --git a/drivers/gpu/drm/nouveau/include/nvkm/subdev/pci.h b/drivers/gpu/drm/nouveau/include/nvkm/subdev/pci.h index 112b674ed9c8a..0172e0d200f81 100644 --- a/drivers/gpu/drm/nouveau/include/nvkm/subdev/pci.h +++ b/drivers/gpu/drm/nouveau/include/nvkm/subdev/pci.h @@ -46,6 +46,7 @@ int nv4c_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct n int g84_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **); int g92_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **); int g94_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **); +int mcp79_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **); int gf100_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **); int gf106_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **); int gk104_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **); diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c index 3738c4664fb6a..305b16d9bcc7a 100644 --- a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c +++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c @@ -1237,7 +1237,7 @@ nvac_chipset = { .mc = { 0x00000001, g98_mc_new }, .mmu = { 0x00000001, mcp77_mmu_new }, .mxm = { 0x00000001, nv50_mxm_new }, - .pci = { 0x00000001, g94_pci_new }, + .pci = { 0x00000001, mcp79_pci_new }, .therm = { 0x00000001, g84_therm_new }, .timer = { 0x00000001, nv41_timer_new }, .volt = { 0x00000001, nv40_volt_new }, diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/pci/Kbuild b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/Kbuild index a14ea0f7b1c87..90f03baeb22ac 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/pci/Kbuild +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/Kbuild @@ -9,6 +9,7 @@ nvkm-y += nvkm/subdev/pci/nv4c.o nvkm-y += nvkm/subdev/pci/g84.o nvkm-y += nvkm/subdev/pci/g92.o nvkm-y += nvkm/subdev/pci/g94.o +nvkm-y += nvkm/subdev/pci/mcp79.o nvkm-y += nvkm/subdev/pci/gf100.o nvkm-y += nvkm/subdev/pci/gf106.o nvkm-y += nvkm/subdev/pci/gk104.o diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/pci/mcp79.c b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/mcp79.c new file mode 100644 index 0000000000000..e2ae242f1aa77 --- /dev/null +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/mcp79.c @@ -0,0 +1,35 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright 2026 Marek Czernohous + * + * MCP79/MCP7A (NVAC): like g94, but MSI re-arm goes through real PCI + * config space. The MMIO-mirror re-arm is unreliable on this IGP and a + * missed re-arm kills the interrupt line (see the nv46 comment; g92 + * already re-arms through config space for the same reason). + */ +#include "priv.h" + +static const struct nvkm_pci_func +mcp79_pci_func = { + .cfg = { .addr = 0x088000, .size = 0x1000 }, + + .init = g84_pci_init, + .msi_rearm = nv46_pci_msi_rearm, + + .pcie.init = g84_pcie_init, + .pcie.set_link = g84_pcie_set_link, + + .pcie.max_speed = g84_pcie_max_speed, + .pcie.cur_speed = g84_pcie_cur_speed, + + .pcie.set_version = g84_pcie_set_version, + .pcie.version = g84_pcie_version, + .pcie.version_supported = g92_pcie_version_supported, +}; + +int +mcp79_pci_new(struct nvkm_device *device, enum nvkm_subdev_type type, int inst, + struct nvkm_pci **ppci) +{ + return nvkm_pci_new_(&mcp79_pci_func, device, type, inst, ppci); +} -- 2.53.0