[PATCH] kbd: Add option for keyboard polling

[Paul Menzel]

From: Marc Jones 
Date: Wed, 24 Sep 2014 15:14:41 -0600

Some devices don’t have legacy interrupt support, but still need to use
a legacy keyboard. This patch adds a KBC check and manual call to the
keyboard service if there is a key waiting in the KBC.

BUG=chrome-os-partner:30836
BRANCH=None
TEST=Build and boot Rambi SeaBIOS.

Change-Id: I11033d29ec26b5a772588a0aa1a35678ab05a462
Signed-off-by: Marc Jones 
Reviewed-on: https://chromium-review.googlesource.com/219803
Reviewed-by: Mike Loptien 
Tested-by: Mike Loptien 
Reviewed-by: Duncan Laurie 
Reviewed-on: https://chromium-review.googlesource.com/227501
Commit-Queue: Stefan Reinauer 
Tested-by: Stefan Reinauer 
Signed-off-by: Paul Menzel 
---
  src/Kconfig |  5 +++++
  src/boot.c  |  3 +++
  src/kbd.c   | 12 ++++++++++++
  3 files changed, 20 insertions(+)

diff --git a/src/Kconfig b/src/Kconfig
index 6606ce4..d389ede 100644
--- a/src/Kconfig
+++ b/src/Kconfig
@@ -440,6 +440,11 @@ menu "BIOS interfaces"
          default y
          help
              Support for int15c2 mouse calls.
+    config KBC_POLL
+        bool "Poll the keyboad controller for keys"
+        default n
+        help
+            Poll for keys when interrupts are not available.

config S3_RESUME
          bool "S3 resume"
diff --git a/src/boot.c b/src/boot.c
index afeb36a..3beecee 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -631,7 +631,10 @@ get_keystroke_full(int msec)
              return get_raw_keystroke();
          if (irqtimer_check(end))
              return -1;
+     if (!CONFIG_KBC_POLL)
          yield_toirq();
+     else
+        msleep(5);
      }
  }

diff --git a/src/kbd.c b/src/kbd.c
index 3f08d32..5726274 100644
--- a/src/kbd.c
+++ b/src/kbd.c
@@ -252,6 +252,18 @@ handle_16(struct bregs *regs)
      // XXX - set_leds should be called from irq handler
      set_leds();

+    // If interrupts are not enabled do KBC polling.
+    // Check the KBC for a key on every keyboard service function (INT16).
+    // If interrupts are working the KBC status port should always be 
empty.
+    // (Yes, there is a race condition, but it is recoverable).
+    if (CONFIG_PS2PORT && CONFIG_KBC_POLL) {
+        u8 v = inb(PORT_PS2_STATUS);
+        if ((v & I8042_STR_OBF) && !(v & I8042_STR_AUXDATA)) {
+            v = inb(PORT_PS2_DATA);
+            process_key(v);
+        }
+    }
+
      switch (regs->ah) {
      case 0x00: handle_1600(regs); break;
      case 0x01: handle_1601(regs); break;

[Gerd Hoffmann]

> Some devices don’t have legacy interrupt support, but still need to use
> a legacy keyboard. This patch adds a KBC check and manual call to the
> keyboard service if there is a key waiting in the KBC.
> diff --git a/src/Kconfig b/src/Kconfig
> index 6606ce4..d389ede 100644
> --- a/src/Kconfig
> +++ b/src/Kconfig
> @@ -440,6 +440,11 @@ menu "BIOS interfaces"
>          default y
>          help
>              Support for int15c2 mouse calls.
> config KBC_POLL
>    bool "Poll the keyboad controller for keys"
>    default n
>    help
>        Poll for keys when interrupts are not available.

Note we already have CONFIG_HARDWARE_IRQ.
So, do we actually need this new config option?

cheers,
  Gerd

[Matt DeVillier]

Disabling hardware IRQ is sufficient on Baytrail ChromeOS devices like
Rambi, so I'd say no

On Tue, Mar 17, 2020, 9:34 AM Gerd Hoffmann  wrote:
> > Some devices don’t have legacy interrupt support, but still need to use
> > a legacy keyboard. This patch adds a KBC check and manual call to the
> > keyboard service if there is a key waiting in the KBC.
> > diff --git a/src/Kconfig b/src/Kconfig
> > index 6606ce4..d389ede 100644
> > --- a/src/Kconfig
> > +++ b/src/Kconfig
> > @@ -440,6 +440,11 @@ menu "BIOS interfaces"
> >          default y
> >          help
> >              Support for int15c2 mouse calls.
> > config KBC_POLL
> >    bool "Poll the keyboad controller for keys"
> >    default n
> >    help
> >        Poll for keys when interrupts are not available.
>
> Note we already have CONFIG_HARDWARE_IRQ.
> So, do we actually need this new config option?
>
> cheers,
>   Gerd
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