Disable PCIe ASPM through kernel command line for iq-8275-evk#1313
Disable PCIe ASPM through kernel command line for iq-8275-evk#1313krishnachaitanya-linux wants to merge 1 commit intoqualcomm-linux:masterfrom
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As discussed offline, both RB4 and RB8 have some link stability issues with ASPM. But this commit just disables ASPM for all boards, which is wrong. This cmdline param should be passed in the relevant machine config file in |
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ok I will raise for conf/machine/iq-8275-evk.conf as this affecting rb4 for now in new PR and close this one. |
When PCIe ASPM is enabled, WLAN functionality is completly broken. There are some connectivity issues in this platform mostly with CLKREQ# pin. To resolve this disable ASPM using kernel command line. Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
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Instead of creating new one, reopened the same PR with new patch. |
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@krishnachaitanya-linux Don't you need the same change for RB8? |
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Also beware that this cmdline param disables all ASPM states, not just L1ss where the issue is currently. So there is power penalty. |
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we are not hitting this issue in RB8 yet for now, may be due to pwrctrl the athk driver is probing after PCIe controller is enabling L1ss. we can raise the patch for RB8 separately. We are hoping to solve this L1ss issue next week. |
There is no other way currently to disable L1ss unless a driver change, like I said in the previous reply, we are hoping to close this by next week, then we will come with proper solution, untill then to unblock test teams we can use this. |
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@krishnachaitanya-linux IMHO using the kernel command line for this purpose is not appropriate. command line is for user configurations, not for masking underlying issues. The correct approach here is to root cause and fix the issues that are causing WLAN failures. If disabling PCIe ASPM is indeed the ultimate fix, please apply it through the defconfig rather than via the kernel command line. |
I think you mean DT / Driver here. |
+1, we should work to avoid any custom kernel command line here, as we want the kernel to work as it would work on any other generic distribution (e.g. with systemready we are not supposed to add custom kernel command line arguments). So NAK from my side. |
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@Mani-Sadhasivam do we have a conclusion on how this should be handled? Should ASPM be disabled for those platforms? |
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@krishnachaitanya-linux If the ASPM root cause is not yet found, then disable ASPM for Root Port in controller driver based on the board compatible. |
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Per @Mani-Sadhasivam , this should be handled in the kernel driver. I totally agree with that conclusion. Closing. |
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PCIe ASPM is not working with the current boards, so disable ASPM with kernel command line.