[edk2-devel] [PATCH 1/2] Silicon/Broadcom/BcmGenetDxe: Delay for linkup in transmit

[Samer El-Haj-Mahmoud]

+Ard's new e-mail address

> -----Original Message-----
> From: Jeremy Linton <jeremy.linton at arm.com>
> Sent: Thursday, April 15, 2021 3:22 PM
> To: devel at edk2.groups.io
> Cc: Ard Biesheuvel <Ard.Biesheuvel at arm.com>; leif at nuviainc.com;
> pete at akeo.ie; Samer El-Haj-Mahmoud <Samer.El-Haj-
> Mahmoud at arm.com>; Andrei Warkentin (awarkentin at vmware.com)
> <awarkentin at vmware.com>; Jeremy Linton <Jeremy.Linton at arm.com>
> Subject: [PATCH 1/2] Silicon/Broadcom/BcmGenetDxe: Delay for linkup in
> transmit
>
> Under normal circumstances GenetSimpleNetworkTransmit won't be called
> unless the rest of the network stack detects the link is up. So, during normal
> operation when the adapter is initialized the link naturally transitions to link
> up, and then is ready for activity later in the boot sequence. If that hasn't
> happened by the time PXE runs then it will itself wait for the link.
>
> OTOH, the normal distro PXE sequence involves PXE loading shim which in
> turn loads grub, which tries to read machine specific configs, modules, and
> grub.cfg in order to prepare the boot menu.
> Then, once a grub selection is picked, it might try to load the
> kernel+initrd.
>
> In this sequence the network stack is shutdown and restarted multiple times.
> Grub though, starts up, notices its been network booted, reads saved
> network parameters and immediately tries to transmit data assuming the link
> is still up.
>
> When that happens grub will print "couldn't send network packet"
> and if that lasts long enough it fails to load grub.cfg and the user gets
> dropped to the grub prompt because no one in the path bothers to assure
> the link state has transitioned back up.
>
> For reference: https://github.com/pftf/RPi4/issues/113
>
> Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
> ---
>  .../Drivers/Net/BcmGenetDxe/SimpleNetwork.c        | 24
> ++++++++++++++++++++--
>  1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/Silicon/Broadcom/Drivers/Net/BcmGenetDxe/SimpleNetwork.c
> b/Silicon/Broadcom/Drivers/Net/BcmGenetDxe/SimpleNetwork.c
> index 1bda18f157..29c76d8495 100644
> --- a/Silicon/Broadcom/Drivers/Net/BcmGenetDxe/SimpleNetwork.c
> +++ b/Silicon/Broadcom/Drivers/Net/BcmGenetDxe/SimpleNetwork.c
> @@ -13,6 +13,7 @@
>  #include <Library/DebugLib.h>
>  #include <Library/DmaLib.h>
>  #include <Library/NetLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
>  #include <Protocol/SimpleNetwork.h>
>
>  #include "BcmGenetDxe.h"
> @@ -590,9 +591,28 @@ GenetSimpleNetworkTransmit (
>
>    if (!Genet->SnpMode.MediaPresent) {
>      //
> -    // Don't bother transmitting if there's no link.
> +    // We should only really get here if the link was up
> +    // and is now down due to a stop/shutdown sequence, and
> +    // the app (grub) doesn't bother to check link state
> +    // because it was up a moment before.
> +    // Lets wait a bit for the link to resume, rather than
> +    // failing to send. In the case of grub it works either way
> +    // but we can't be sure that is universally true, and
> +    // hanging for a couple seconds is nicer than a screen of
> +    // grub send failure messages.
>      //
> -    return EFI_NOT_READY;
> +    int retries = 1000;
> +    DEBUG ((DEBUG_INFO, "%a: Waiting 10s for link\n", __FUNCTION__));
> +    do {
> +      gBS->Stall (10000);
> +      Status = GenericPhyUpdateConfig (&Genet->Phy);
> +    } while (EFI_ERROR (Status) && retries--);
> +    if (EFI_ERROR (Status)) {
> +      DEBUG ((DEBUG_ERROR, "%a: no link\n", __FUNCTION__));
> +      return EFI_NOT_READY;
> +    } else {
> +      Genet->SnpMode.MediaPresent = TRUE;
> +    }
>    }
>
>    if (HeaderSize != 0) {
> --
> 2.13.7

IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.


-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#74900): https://edk2.groups.io/g/devel/message/74900
Mute This Topic: https://groups.io/mt/82125863/1813853
Group Owner: devel+owner at edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [edk2-devel-archive at redhat.com]
-=-=-=-=-=-=-=-=-=-=-=-