From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2EA7437AA71 for ; Fri, 27 Feb 2026 10:03:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772186581; cv=none; b=dk+Yc8cJYydfPMbkEwRGbxONs0UA4mI042hyfYl30j5lLQYdpXmWuPN4lIocXtnAtiEpGFtNjSgaMuJ+byu/XliwUpKotXSgrqhzeCAwUmg4Dl3SIwZkpDIYIVPMzSO/acaaaftYGk0LT5TQBELylbu2C3IS+Cmw6N3gansIyHA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772186581; c=relaxed/simple; bh=sISMdSV3MNe6kKHUHQrwVRu3NlbGB3BBMRsgKKDIT+I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XWCCAjIK3nL4o6pSy9/eiZICKrDTHP6rIHHLiV4vi7lRqhw2+H81xmoCAA5sCGsqk6ANKeYUBjmJP42xb/qvuA9QBadgZ2WgVb5nqNsRvD2sE61DLbnXhnUsVyMgk5H4HDn+tPm/Bm6Mbx45ZzGnTns/WlgXzs4CR5l2Gl8r/CQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S5J9irtk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S5J9irtk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7424C116C6; Fri, 27 Feb 2026 10:02:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772186581; bh=sISMdSV3MNe6kKHUHQrwVRu3NlbGB3BBMRsgKKDIT+I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=S5J9irtkImNgOvUchtE2Y8u8nvLaypnpZHgv5io9ECXRTfnI1cORhtOuhEK/vHsdr x0wiYZ1FE+iylyYacAB0us+I8h0CJofwVPYdr/Lm+GGHfvbHmOFD0ODdjIlcUioc0k W9guaB/I2nyJPGgr+ZGe/fz3ctp6jG0lHP7z+yUTd1/AjW8/4SR7fNvIOo35xkvtMf EpewwUY0Oq492yw0PLisp9tn4/fOsbx7H/5T7FyKTbfMbulGpumMO+rK3/+npTJZVl xr/giDoZLFd/xsDXNT82zYyQr1jrtjBxqnRJDjhHkVG2lZWKeUZbkL8bHs2kyxGfkK vjmayruymALHg== Date: Fri, 27 Feb 2026 11:02:55 +0100 From: Benjamin Tissoires To: "Nautiyal, Ankit K" Cc: Jani Nikula , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , David Airlie , Simona Vetter , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/i915/vrr: partial revert of dda7dcd9da73c5327aef42b89f0519bb51e84217 Message-ID: References: <20260218-wip-fix-iris-plus-v1-1-e6b969defd6d@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Feb 20 2026, Nautiyal, Ankit K wrote: > > On 2/18/2026 9:53 PM, Benjamin Tissoires wrote: > > Commit dda7dcd9da73 ("drm/i915/vrr: Use fixed timings for platforms that > > support VRR") introduced a regression on my Ice Lake laptop with an Iris > > Plus G7. > > > > The screen can go blank (screen lock or just idle), but if I try to wake > > it up, there is an immediate kernel lock. The netconsole was really > > unhelpful here, and a bisect gave me the commit above to be the culprit. > > > > For reference, the netconsole I could get was: > > [ 103.553110] netconsole: network logging started > > [ 125.642395] mce: [Hardware Error]: CPU 0: Machine Check Exception: 5 Bank 6: ba00000011000402 > > [ 125.642400] mce: [Hardware Error]: RIP !INEXACT! 33:<00007fa4471665ec> > > [ 125.642403] mce: [Hardware Error]: TSC 38282e339d > > [ 125.642404] mce: [Hardware Error]: PROCESSOR 0:706e5 TIME 1771365482 SOCKET 0 APIC 0 microcode ca > > [ 125.642406] mce: [Hardware Error]: Run the above through 'mcelog --ascii' > > [ 125.642406] mce: [Hardware Error]: Machine check: Processor context corrupt > > [ 125.642407] Kernel panic - not syncing: Fatal machine check > > [ 125.642415] Kernel Offset: 0x1d400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) > > > > and then the backtrace lead to the netconsole in itself. > > > > If I restore the early return when vmin >= vmax (in my case vmin==vmax), > > then I can use my machine again after it goes idle. > > > > I have strictly no ideas if this is the correct solution, so please take > > this with a grain of salt, but this is effectively preventing me to use > > distro kernel since v6.16. > > > Hi Benjamin, > > Thanks for bisecting and getting the problematic commit. > > This seem to be an issue while trying to fill few VRR related stuff. Your > change effectively makes an early return from the > intel_vrr_compute_config(), probably avoiding setting those VRR related > parameters in sw state. > > To understand the issue better and to debug further I request you to file a > bug for i915 in gitlab [1] . More details in [2]. > > Also request you to test with the latest drm-tip : [3], and attach the logs > from boot. The link [2] has the necessary details. Both done: - drm-tip still shows the crash - issue filed at https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15777 Sorry for not coming back earlier, got my plate full this week. Cheers, Benjamin > > > Links: > > [1] https://gitlab.freedesktop.org/drm/i915/kernel/-/issues > > [2] https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html > > [3] https://gitlab.freedesktop.org/drm/tip/-/commits/drm-tip > > > Thanks & Regards, > > Ankit > > > > > > > Signed-off-by: Benjamin Tissoires > > --- > > I've been experiencing this bug since kernel v6.16. > > > > System Information > > Manufacturer: Dell Inc. > > Product Name: XPS 13 7390 2-in-1 > > > > cpu: Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz > > > > lspci: > > 00:00.0 Host bridge [0600]: Intel Corporation Ice Lake-LP Processor Host Bridge/DRAM Registers [8086:8a12] (rev 03) > > Subsystem: Dell Device [1028:08b0] > > Flags: bus master, fast devsel, latency 0, IOMMU group 2 > > Capabilities: > > Kernel driver in use: icl_uncore > > > > 00:02.0 VGA compatible controller [0300]: Intel Corporation Iris Plus Graphics G7 [8086:8a52] (rev 07) (prog-if 00 [VGA controller]) > > DeviceName: To Be Filled by O.E.M. > > Subsystem: Dell Device [1028:08b0] > > Flags: bus master, fast devsel, latency 0, IRQ 188, IOMMU group 1 > > Memory at 603d000000 (64-bit, non-prefetchable) [size=16M] > > Memory at 4000000000 (64-bit, prefetchable) [size=256M] > > I/O ports at 4000 [size=64] > > Expansion ROM at 000c0000 [virtual] [disabled] [size=128K] > > Capabilities: > > Kernel driver in use: i915 > > Kernel modules: i915 > > > > Again, I have really no idea if this is the correct fix, but it would be > > nice if the issue could be solved in v7.0 and backported to older > > kernels. > > > > Please tell me if I need to provide more information. > > > > Cheers, > > Benjamin > > --- > > drivers/gpu/drm/i915/display/intel_vrr.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c > > index b92c42fde937..3d16dd4611d9 100644 > > --- a/drivers/gpu/drm/i915/display/intel_vrr.c > > +++ b/drivers/gpu/drm/i915/display/intel_vrr.c > > @@ -377,6 +377,9 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state, > > vmax = vmin; > > } > > + if (vmin >= vmax) > > + return; > > + > > if (crtc_state->uapi.vrr_enabled && vmin < vmax) > > intel_vrr_compute_vrr_timings(crtc_state, vmin, vmax); > > else if (is_cmrr_frac_required(crtc_state) && is_edp) > > > > --- > > base-commit: 05f7e89ab9731565d8a62e3b5d1ec206485eeb0b > > change-id: 20260218-wip-fix-iris-plus-28a916221bdc > > > > Best regards,