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pciexp_device: Remove useless write on a read-only register 

The Role-Based Error Reporting is not a configurable field,
it's a read only field in the Device Capability register.
This code was old and comes from commit f6eb88ad but evidently
is not useful in any way. The PCIe Specification [1] states
that it's read-only and must always be set to 1.

I have also done tests on purism/librem13 hardware, trying to
change that value, without any success.

[1]: PCI Express Base Specification Revision 3.0
     Page 612

Change-Id: I729617a5c6f4f52dfc4c422df78379b309066399
Signed-off-by: Youness Alaoui <youness.alaoui@puri.sm>
Reviewed-on: https://review.coreboot.org/19901
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Reviewed-by: Martin Roth <martinroth@google.com>
This commit is contained in:
Youness Alaoui 2017-05-24 17:47:27 -04:00 committed by Martin Roth
parent b191c9f0ab
commit 2f48b7b1e9
1 changed files with 0 additions and 5 deletions
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5
src/device/pciexp_device.c
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@ -361,11 +361,6 @@ static void pciexp_enable_aspm(device_t root, unsigned root_cap,
lnkctl = pci_read_config16(endp, endp_cap + PCI_EXP_LNKCTL);
lnkctl |= apmc;
pci_write_config16(endp, endp_cap + PCI_EXP_LNKCTL, lnkctl);
/* Enable ASPM role based error reporting. */
devcap = pci_read_config32(endp, endp_cap + PCI_EXP_DEVCAP);
devcap |= PCI_EXP_DEVCAP_RBER;
pci_write_config32(endp, endp_cap + PCI_EXP_DEVCAP, devcap);
}
printk(BIOS_INFO, "ASPM: Enabled %s\n", aspm_type_str[apmc]);