In the case where lmem_size < dsm_base, hardware is reporting that stolen lmem is unusable. In this case, instead of throwing a warning, we can continue execution as normal by disabling stolen LMEM support. For example, this change will allow the following error report from ATS-M to no longer apply:
<6> [144.859887] pcieport 0000:4b:00.0: bridge window [mem 0xb1000000-0xb11fffff] <6> [144.859900] pcieport 0000:4b:00.0: bridge window [mem 0x3bbc00000000-0x3bbc17ffffff 64bit pref] <6> [144.859917] pcieport 0000:4c:01.0: PCI bridge to [bus 4d-4e] <6> [144.859932] pcieport 0000:4c:01.0: bridge window [mem 0xb1000000-0xb11fffff] <6> [144.859945] pcieport 0000:4c:01.0: bridge window [mem 0x3bbc00000000-0x3bbc17ffffff 64bit pref] <6> [144.859984] i915 0000:4d:00.0: [drm] BAR2 resized to 256M <6> [144.860640] i915 0000:4d:00.0: [drm] Using a reduced BAR size of 256MiB. Consider enabling 'Resizable BAR' or similar, if available in the BIOS. <4> [144.860719] -----------[ cut here ]----------- <4> [144.860727] WARNING: CPU: 17 PID: 1815 at drivers/gpu/drm/i915/gem/i915_gem_stolen.c:939 i915_gem_stolen_lmem_setup+0x38c/0x430 [i915] <4> [144.861430] Modules linked in: i915 snd_intel_dspcfg snd_hda_codec snd_hwdep snd_hda_core snd_pcm vgem drm_shmem_helper prime_numbers i2c_algo_bit ttm video drm_display_helper drm_buddy fuse x86_pkg_temp_thermal coretemp kvm_intel kvm ixgbe mdio irqbypass ptp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pps_core i2c_i801 mei_me i2c_smbus mei wmi acpi_power_meter [last unloaded: i915] <4> [144.861611] CPU: 17 PID: 1815 Comm: i915_module_loa Tainted: G U 6.8.0-rc5-drmtip_1515-g78f49af27723+ #1 <4> [144.861624] Hardware name: Intel Corporation WHITLEY/WHITLEY, BIOS SE5C6200.86B.0020.P41.2109300305 09/30/2021 <4> [144.861632] RIP: 0010:i915_gem_stolen_lmem_setup+0x38c/0x430 [i915] <4> [144.862287] Code: ff 41 c1 e4 05 e9 ac fe ff ff 4d 63 e4 48 89 ef 48 85 ed 74 04 48 8b 7d 08 48 c7 c6 10 a3 7b a0 e8 e9 90 43 e1 e9 ee fd ff ff <0f> 0b 49 c7 c4 ed ff ff ff e9 e0 fd ff ff 0f b7 d2 48 c7 c6 00 d9 <4> [144.862299] RSP: 0018:ffffc90005607980 EFLAGS: 00010207 <4> [144.862315] RAX: fffffffffff00000 RBX: 0000000000000003 RCX: 0000000000000000 Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10833 Suggested-by: Chris Wilson <chris.p.wil...@linux.intel.com> Signed-off-by: Jonathan Cavitt <jonathan.cav...@intel.com> --- v2: - Return 0 to allow execution to continue - Remove white space in commit message - s/Fixes/Closes drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c index ad6dd7f3259bc..4d60a5b375053 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c @@ -936,8 +936,12 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type, } else { /* Use DSM base address instead for stolen memory */ dsm_base = intel_uncore_read64(uncore, GEN6_DSMBASE) & GEN11_BDSM_MASK; - if (WARN_ON(lmem_size < dsm_base)) - return ERR_PTR(-ENODEV); + if (lmem_size < dsm_base) { + drm_dbg(&i915->drm, + "Disabling stolen memory support due to OOB placement: lmem_size = %lli vs dsm_base = %lli\n", + lmem_size, dsm_base); + return 0; + } dsm_size = ALIGN_DOWN(lmem_size - dsm_base, SZ_1M); } -- 2.25.1
