lkml.org 
[lkml]   [2020]   [Mar]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v17 09/12] PCI/AER: Allow clearing Error Status Register in FF mode
Date
On 3/10/2020 3:44 PM, Kuppuswamy Sathyanarayanan wrote:
>
<snip>
>
> Please check the following spec reference (change to 4.5.1 Table 4-6)
>
> the OS is permitted to read or write DPC Control and Status registers of a
> port while processing an Error Disconnect Recover notification from firmware
> on that port. Error Disconnect Recover notification processing begins
> with the
> Error Disconnect Recover notify from Firmware, and *ends when the OS
> releases
> DPC by clearing the DPC Trigger Status bit*.Firmware can read DPC Trigger
> Status bit to determine the ownership of DPC Control and Status
> registers. Firmware
> is not permitted to write to DPC Control and Status registers if DPC
> Trigger Status is
> set i.e. the link is in DPC state. *Outside of the Error Disconnect
> Recover notification
> processing window, the OS is not permitted to modify DPC Control or
> Status registers*;
> only firmware is allowed to.
>
> Since the EDR processing window ends with clearing DPC Trigger status
> bit, OS needs to
> clear DPC and AER registers before it ends.
>
> Austin,
>
> I think the order needs to be reversed in the implementation note.

Agreed.

\
 
 \ /
  Last update: 2020-03-10 21:50    [W:0.129 / U:0.148 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site