hw/arm/bcm2835_property: Add support for RPI_FIRMWARE_FRAMEBUFFER_GET_NUM_DISPLAYS

In more recent Raspbian OS Linux kernels, the fb driver gives up
immediately if RPI_FIRMWARE_FRAMEBUFFER_GET_NUM_DISPLAYS fails or no
displays are reported.

This change simply always reports one display. It makes bcm2835_fb work
again with these more recent kernels.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Enrik Berkhan <Enrik.Berkhan@inka.de>
Message-Id: <20220812143519.59134-1-Enrik.Berkhan@inka.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/hw/misc/bcm2835_property.c b/hw/misc/bcm2835_property.c
index e94e951057ec815236479a189cfc30f5923121aa..890ae7bae56c628b6bebe773cba9289bd4bf706c 100644 (file)
--- a/hw/misc/bcm2835_property.c
+++ b/hw/misc/bcm2835_property.c
@@ -270,6 +270,10 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             stl_le_phys(&s->dma_as, value + 12, 0);
             resplen = 4;
             break;
+        case 0x00040013: /* Get number of displays */
+            stl_le_phys(&s->dma_as, value + 12, 1);
+            resplen = 4;
+            break;
 
         case 0x00060001: /* Get DMA channels */
             /* channels 2-5 */