Track the LED intensity, and emit a trace event when it changes.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/misc/led.h | 1 +
 hw/misc/led.c         | 5 +++++
 hw/misc/trace-events  | 1 +
 3 files changed, 7 insertions(+)

diff --git a/include/hw/misc/led.h b/include/hw/misc/led.h
index 883006bb8f..df5b32a2db 100644
--- a/include/hw/misc/led.h
+++ b/include/hw/misc/led.h
@@ -35,6 +35,7 @@ typedef struct LEDState {
     DeviceState parent_obj;
     /* Public */
 
+    uint16_t current_intensity;
     qemu_irq irq;
 
     /* Properties */
diff --git a/hw/misc/led.c b/hw/misc/led.c
index 8503dde777..37d9f1f3d2 100644
--- a/hw/misc/led.c
+++ b/hw/misc/led.c
@@ -32,6 +32,11 @@ void led_set_intensity(LEDState *s, uint16_t new_intensity)
 {
     trace_led_set_intensity(s->description ? s->description : "n/a",
                             s->color, new_intensity);
+    if (new_intensity != s->current_intensity) {
+        trace_led_change_intensity(s->description ? s->description : "n/a",
+                                   s->color,
+                                   s->current_intensity, new_intensity);
+    }
     s->current_intensity = new_intensity;
 }
 
diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index f58853d367..57d39bf9b9 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -209,6 +209,7 @@ grlib_apb_pnp_read(uint64_t addr, uint32_t value) "APB PnP read addr:0x%03"PRIx6
 
 # led.c
 led_set_intensity(const char *color, const char *desc, uint16_t intensity) "LED desc:'%s' color:%s intensity: 0x%04"PRIx16
+led_change_intensity(const char *color, const char *desc, uint16_t old_intensity, uint16_t new_intensity) "LED desc:'%s' color:%s intensity 0x%04"PRIx16" -> 0x%04"PRIx16""
 
 # pca9552.c
 pca9552_gpio_status(const char *description, const char *buf) "%s GPIOs 0-15 [%s]"
-- 
2.21.3

On 6/20/20 4:07 PM, Philippe Mathieu-Daudé wrote:
> Track the LED intensity, and emit a trace event when it changes.
> 
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  include/hw/misc/led.h | 1 +
>  hw/misc/led.c         | 5 +++++
>  hw/misc/trace-events  | 1 +
>  3 files changed, 7 insertions(+)
> 
> diff --git a/include/hw/misc/led.h b/include/hw/misc/led.h
> index 883006bb8f..df5b32a2db 100644
> --- a/include/hw/misc/led.h
> +++ b/include/hw/misc/led.h
> @@ -35,6 +35,7 @@ typedef struct LEDState {
>      DeviceState parent_obj;
>      /* Public */
>  
> +    uint16_t current_intensity;
>      qemu_irq irq;

Why not sort this new field next to the other uint16_t and (partially) fill the
hole?

Otherwise,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~

On 6/21/20 9:23 PM, Richard Henderson wrote:
> On 6/20/20 4:07 PM, Philippe Mathieu-Daudé wrote:
>> Track the LED intensity, and emit a trace event when it changes.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>>  include/hw/misc/led.h | 1 +
>>  hw/misc/led.c         | 5 +++++
>>  hw/misc/trace-events  | 1 +
>>  3 files changed, 7 insertions(+)
>>
>> diff --git a/include/hw/misc/led.h b/include/hw/misc/led.h
>> index 883006bb8f..df5b32a2db 100644
>> --- a/include/hw/misc/led.h
>> +++ b/include/hw/misc/led.h
>> @@ -35,6 +35,7 @@ typedef struct LEDState {
>>      DeviceState parent_obj;
>>      /* Public */
>>  
>> +    uint16_t current_intensity;
>>      qemu_irq irq;
> 
> Why not sort this new field next to the other uint16_t and (partially) fill the
> hole?

From a reviewer point of view, I prefer to keep the state fields
separated from the properties fields, wasting few bits of RAM.

Anyway I switched to a percent value. What is better to hold
it, an 'unsigned' or 'uint8_t' type?

> 
> Otherwise,
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Thanks!

> 
> 
> r~
> 

On 6/21/20 3:25 PM, Philippe Mathieu-Daudé wrote:
> Anyway I switched to a percent value. What is better to hold
> it, an 'unsigned' or 'uint8_t' type?

Might as well use unsigned; you'll not be saving space with uint8_t.


r~

On 6/22/20 6:48 PM, Richard Henderson wrote:
> On 6/21/20 3:25 PM, Philippe Mathieu-Daudé wrote:
>> Anyway I switched to a percent value. What is better to hold
>> it, an 'unsigned' or 'uint8_t' type?
> 
> Might as well use unsigned; you'll not be saving space with uint8_t.

Bah if we want to migrate the intensity, we can't use 'unsigned',
so I'll keep uint8_t / VMSTATE_UINT8.