On 18 April 2018 at 00:14, Joonas Lahtinen joonas.lahtinen@linux.intel.com wrote:
Quoting Jani Nikula (2018-04-17 12:02:52)
On Mon, 16 Apr 2018, "Srivatsa, Anusha" anusha.srivatsa@intel.com wrote:
-----Original Message----- From: Jani Nikula [mailto:jani.nikula@linux.intel.com] Sent: Wednesday, April 11, 2018 5:27 AM To: Ian W MORRISON ianwmorrison@gmail.com Cc: Vivi, Rodrigo rodrigo.vivi@intel.com; Srivatsa, Anusha anusha.srivatsa@intel.com; Wajdeczko, Michal Michal.Wajdeczko@intel.com; Greg KH gregkh@linuxfoundation.org; airlied@linux.ie; joonas.lahtinen@linux.intel.com; linux-kernel@vger.kernel.org; stable@vger.kernel.org; intel-gfx@lists.freedesktop.org; dri- devel@lists.freedesktop.org Subject: Re: [RESEND PATCH 1/1] drm/i915/glk: Add MODULE_FIRMWARE for Geminilake
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In summary so far:
Jani:
NAK on indiscriminate Cc: stable. There are zero guarantees that older kernels will work with whatever firmware you throw at them. Who tested the firmware with v4.12 and later? We only have the CI results against *current* drm-tip. We don't even know about v4.16. I'm not going to ack and take responsibility for the stable backports unless someone actually comes forward with credible Tested-bys.
Anusha:
The stable kernel version is 4.12 and beyond. It is appropriate to add the CC: stable in my opinion
Joonas:
And even then, some distros will be surprised of the new MODULE_FIRMWARE and will need to update the linux-firmware package, too.
I've performed backport testing and some additional analysis as follows:
The DMC firmware for GLK was initially included in 4.11 (commit: dbb28b5c3d3cb945a63030fab8d3894cf335ce19). Then the firmware version was upgraded to 1.03 in 4.12 (commit: f4a791819ed00a749a90387aa139706a507aa690). However MODULE_FIRMWARE for the GLK DMC firmware was also removed in 4.12 (commit: d9321a03efcda867b3a8c6327e01808516f0acd7) together with the firmware version being bumped to 1.04 (commit: aebfd1d37194e00d4c417e7be97efeb736cd9c04).
The patch below effectively reverts commit d9321a03 because the GLK firmware is now available in the linux-firmware repository.
To test stable backports I've used Ubuntu 18.04 (Beta 2) userspace with both Ubuntu (generic) and self-compiled mainline (patched) kernels. The conclusion was that the patch works across 4.12 to 4.17-rc1 kernels additionally displaying a 'Possible missing firmware' message when installing a kernel with the expected firmware missing.
The following are abridged backport test results:
Scenario: No DMC (glk_dmc_ver1_04.bin) firmware installed in '/lib/firmware/i915' Test:Kernel installation ('grep -i dmc' output from 'apt install'): 4.12-generic and 4.15-generic: No output # as expected 4.12 to 4.17-rc1-patched: W: Possible missing firmware /lib/firmware/i915/glk_dmc_ver1_04.bin for module i915 Result: The effect of the patch is to add a 'Possible missing firmware' message. Test: Booting ('grep -i dmc' output from 'dmesg'): 4.12-generic: No output # as expected 4.15-generic: i915 0000:00:02.0: Direct firmware load for i915/glk_dmc_ver1_04.bin failed with error -2 i915 0000:00:02.0: Failed to load DMC firmware i915/glk_dmc_ver1_04.bin. Disabling runtime power management. i915 0000:00:02.0: DMC firmware homepage: https://01.org/linuxgraphics/downloads/firmware 4.12-patched: No output # as expected 4.13 to 4.14-patched: i915 0000:00:02.0: Direct firmware load for i915/glk_dmc_ver1_04.bin failed with error -2 i915 0000:00:02.0: Failed to load DMC firmware [https://01.org/linuxgraphics/downloads/firmware], disabling runtime power management. 4.15 to 4.17-rc1-patched: i915 0000:00:02.0: Direct firmware load for i915/glk_dmc_ver1_04.bin failed with error -2 i915 0000:00:02.0: Failed to load DMC firmware i915/glk_dmc_ver1_04.bin. Disabling runtime power management. i915 0000:00:02.0: DMC firmware homepage: https://01.org/linuxgraphics/downloads/firmware Result: The effect of the patch does not change existing (non-patched kernel) messages.
Scenario: DMC (glk_dmc_ver1_04.bin) firmware installed in '/lib/firmware/i915' Test:Kernel installation ('grep -i dmc' output from 'apt install') All kernels: No messages # as expected Result: The effect of the patch does not change existing messages. Test" Booting ('grep -i dmc' output from 'dmesg'): 4.12-generic: No output # as expected 4.15-generic: i915 0000:00:02.0: Direct firmware load for i915/glk_dmc_ver1_04.bin failed with error -2 i915 0000:00:02.0: Failed to load DMC firmware i915/glk_dmc_ver1_04.bin. Disabling runtime power management. i915 0000:00:02.0: DMC firmware homepage: https://01.org/linuxgraphics/downloads/firmware 4.12-patched: No output # as expected 4.13 to 4.17-rc1-patched: [drm] Finished loading DMC firmware i915/glk_dmc_ver1_04.bin (v1.4) Result: The effect of the patch is to remove the 'Failed to load' message.
Regards, Ian