On Fri, Sep 05, 2025 at 01:41:49PM +0300, Jani Nikula wrote:
for_each_set_bit() expects size to be in bits, not bytes. The abox mask iteration uses bytes, but it works by coincidence, because the local variable holding the mask is unsigned long, and the mask only ever has bit 2 as the highest bit. Using a smaller type could lead to subtle and very hard to track bugs.
Fixes: 62afef2811e4 ("drm/i915/rkl: RKL uses ABOX0 for pixel transfers") Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Matt Roper matthew.d.roper@intel.com Cc: stable@vger.kernel.org # v5.9+ Signed-off-by: Jani Nikula jani.nikula@intel.com
Good catch.
Reviewed-by: Matt Roper matthew.d.roper@intel.com
drivers/gpu/drm/i915/display/intel_display_power.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c index 7340d5a71673..6f56ce939f00 100644 --- a/drivers/gpu/drm/i915/display/intel_display_power.c +++ b/drivers/gpu/drm/i915/display/intel_display_power.c @@ -1174,7 +1174,7 @@ static void icl_mbus_init(struct intel_display *display) if (DISPLAY_VER(display) == 12) abox_regs |= BIT(0);
- for_each_set_bit(i, &abox_regs, sizeof(abox_regs))
- for_each_set_bit(i, &abox_regs, BITS_PER_TYPE(abox_regs)) intel_de_rmw(display, MBUS_ABOX_CTL(i), mask, val);
} @@ -1639,11 +1639,11 @@ static void tgl_bw_buddy_init(struct intel_display *display) if (table[config].page_mask == 0) { drm_dbg_kms(display->drm, "Unknown memory configuration; disabling address buddy logic.\n");
for_each_set_bit(i, &abox_mask, sizeof(abox_mask))
for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask)) intel_de_write(display, BW_BUDDY_CTL(i), BW_BUDDY_DISABLE);
for_each_set_bit(i, &abox_mask, sizeof(abox_mask)) {
for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask)) { intel_de_write(display, BW_BUDDY_PAGE_MASK(i), table[config].page_mask);2.47.2